Correct XML comment syntax

- fix problems at least with Roslyn compiler and VS IntelliSense or the Object Browser
 - `<see langref="keyword"/>` generates nothing
 - `<example>` at top level (outside `<summary>`) generates nothing
 - curly braces don't become angle brackets outside `<see cref="reference"/>` references
  - yeah, a point @yishaigalatzer asked about in a previous PR
- `<see href="reference"/>` is not valid
- correct some invalid use of angle brackets and remove useless empty elements
- correct unresolved XML comment references; generally, add namespace prefix

Symptoms for some of the above issues included
- generated XML comments such as `<!-- Badly formed XML comment ... -->`, usually indicating an unclosed element
- generated XML attributes such as `cref="!:..."`, indicating a broken reference
 - in a couple of cases we had `<typeparamref cref="TOption"/>`; attribute should be `"name"`

Few wording changes beyond
- `"opening </form> tag"` -> `"<form> start tag"`
- `"closing </form> tag"` -> `"</form> end tag"`

Also correct two typos in `HtmlHelper`

Will create a unit test to ensure XML syntax doesn't degrade going forward.  Separate PR.
- for now, check using `dir -r *.xml | sls '!'`

src/Microsoft.AspNet.Mvc.Core/ExpiringFileInfoCache.cs

@@ -10,7 +10,7 @@
 namespace Microsoft.AspNet.Mvc.Core
 {
     /// <summary>
-    /// A default implementation for the <see cref="IFileInfoCache" interface./>
+    /// A default implementation for the <see cref="IFileInfoCache"/> interface.
     /// </summary>
     public class ExpiringFileInfoCache : IFileInfoCache
     {

src/Microsoft.AspNet.Mvc.Core/FormContext.cs

@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Generic;
-using Microsoft.AspNet.Mvc.Rendering;
 
 namespace Microsoft.AspNet.Mvc
 {
@@ -14,8 +13,8 @@ public class FormContext
         private Dictionary<string, object> _formData;
 
         /// <summary>
-        /// Property bag for any information you wish to associate with a {form/} in an <see cref="IHtmlHelper"/>
-        /// implementation or extension method.
+        /// Property bag for any information you wish to associate with a &lt;form/&gt; in an
+        /// <see cref="Rendering.IHtmlHelper"/> implementation or extension method.
         /// </summary>
         public IDictionary<string, object> FormData
         {

src/Microsoft.AspNet.Mvc.Core/Formatters/MediaTypeWithQualityHeaderValueComparer.cs

@@ -25,17 +25,15 @@ public static MediaTypeWithQualityHeaderValueComparer QualityComparer
             get { return _mediaTypeComparer; }
         }
 
-        /// <summary>
-        /// Compares two <see cref="MediaTypeWithQualityHeaderValue"/> based on their quality value 
-        /// (a.k.a their "q-value"). Values with identical q-values are considered equal (i.e the result is 0)
-        /// with the exception that sub-type wild-cards are considered less than specific media types and full
-        /// wild-cards are considered less than sub-type wild-cards. This allows to sort a sequence of 
-        /// <see cref="MediaTypeWithQualityHeaderValue"/> following their q-values in the order of specific 
-        /// media types, sub-type wildcards, and last any full wild-cards.
-        /// </summary>
-        /// <param name="mediaType1">The first <see cref="MediaTypeWithQualityHeaderValue"/> to compare.</param>
-        /// <param name="mediaType2">The second <see cref="MediaTypeWithQualityHeaderValue"/> to compare.</param>
-        /// <returns></returns>
+        /// <inheritdoc />
+        /// <remarks>
+        /// Performs comparisons based on the arguments' quality values
+        /// (aka their "q-value"). Values with identical q-values are considered equal (i.e. the result is 0)
+        /// with the exception that subtype wildcards are considered less than specific media types and full
+        /// wildcards are considered less than subtype wildcards. This allows callers to sort a sequence of
+        /// <see cref="MediaTypeWithQualityHeaderValue"/> following their q-values in the order of specific
+        /// media types, subtype wildcards, and last any full wildcards.
+        /// </remarks>
         public int Compare(MediaTypeWithQualityHeaderValue mediaType1, MediaTypeWithQualityHeaderValue mediaType2)
         {
             if (object.ReferenceEquals(mediaType1, mediaType2))

src/Microsoft.AspNet.Mvc.Core/IExpiringFileInfoCache.cs

@@ -14,7 +14,7 @@ public interface IFileInfoCache
         /// Returns a cached <see cref="IFileInfo" /> for a given path.
         /// </summary>
         /// <param name="virtualPath">The virtual path.</param>
-        /// <returns></returns>
+        /// <returns>The cached <see cref="IFileInfo"/>.</returns>
         IFileInfo GetFileInfo(string virtualPath);
     }
 }

src/Microsoft.AspNet.Mvc.Core/MvcOptions.cs

@@ -50,9 +50,9 @@ public AntiForgeryOptions AntiForgeryOptions
         }
 
         public List<OutputFormatterDescriptor> OutputFormatters { get; private set; }
-        
+
         /// <summary>
-        /// Provides programmatic configuration for the default <see cref="IViewEngine" />.
+        /// Provides programmatic configuration for the default <see cref="Rendering.IViewEngine" />.
         /// </summary>
         public RazorViewEngineOptions ViewEngineOptions
         {
@@ -75,17 +75,20 @@ public RazorViewEngineOptions ViewEngineOptions
         }
 
         /// <summary>
-        /// Get a list of the <see cref="ModelBinderDescriptor" /> used by the <see cref="CompositeModelBinder" />.
+        /// Get a list of the <see cref="ModelBinderDescriptor" /> used by the
+        /// <see cref="ModelBinding.CompositeModelBinder" />.
         /// </summary>
         public List<ModelBinderDescriptor> ModelBinders { get; private set; }
 
         /// <summary>
-        /// Gets a list of descriptors that represent <see cref="IViewEngine"/> used by this application.
+        /// Gets a list of descriptors that represent <see cref="Rendering.IViewEngine"/> used
+        /// by this application.
         /// </summary>
         public List<ViewEngineDescriptor> ViewEngines { get; private set; }
 
         /// <summary>
-        /// Gets a list of descriptors that represent <see cref="IValueProviderFactory"/> used by this application.
+        /// Gets a list of descriptors that represent
+        /// <see cref="ModelBinding.IValueProviderFactory"/> used by this application.
         /// </summary>
         public List<ValueProviderFactoryDescriptor> ValueProviderFactories { get; private set; }
 

src/Microsoft.AspNet.Mvc.Core/OptionDescriptors/ModelBinderDescriptor.cs

@@ -14,7 +14,7 @@ public class ModelBinderDescriptor : OptionDescriptor<IModelBinder>
         /// <summary>
         /// Creates a new instance of <see cref="ModelBinderDescriptor"/>.
         /// </summary>
-        /// <param name="type">A type that represents a <see cref="IModelBinder"/>.
+        /// <param name="type">A type that represents a <see cref="IModelBinder"/>.</param>
         public ModelBinderDescriptor([NotNull] Type type)
             : base(type)
         {
@@ -23,7 +23,7 @@ public ModelBinderDescriptor([NotNull] Type type)
         /// <summary>
         /// Creates a new instance of <see cref="ModelBinderDescriptor"/> with the specified instance.
         /// </summary>
-        /// <param name="option">An instance of <see cref="IModelBinder"/>.
+        /// <param name="option">An instance of <see cref="IModelBinder"/>.</param>
         public ModelBinderDescriptor([NotNull] IModelBinder binder)
             : base(binder)
         {

src/Microsoft.AspNet.Mvc.Core/OptionDescriptors/OptionDescriptor.cs

@@ -15,7 +15,7 @@ public class OptionDescriptor<TOption>
         /// <summary>
         /// Creates a new instance of <see cref="OptionDescriptor{TOption}"/>.
         /// </summary>
-        /// <param name="type">A type that represents <typeparamref name="TOption"/>.
+        /// <param name="type">A type that represents <typeparamref name="TOption"/>.</param>
         public OptionDescriptor([NotNull] Type type)
         {
             var optionType = typeof(TOption);
@@ -31,15 +31,15 @@ public OptionDescriptor([NotNull] Type type)
         /// <summary>
         /// Creates a new instance of <see cref="OptionDescriptor{TOption}"/> with the specified instance.
         /// </summary>
-        /// <param name="option">An instance of <typeparamref cref="TOption"/> that the descriptor represents.</param>
+        /// <param name="option">An instance of <typeparamref name="TOption"/> that the descriptor represents.</param>
         public OptionDescriptor([NotNull] TOption option)
         {
             Instance = option;
             OptionType = option.GetType();
         }
 
         /// <summary>
-        /// Gets the type of the <typeparamref cref="TOption"/> described by this 
+        /// Gets the type of the <typeparamref name="TOption"/> described by this
         /// <see cref="OptionDescriptor{TOption}"/>.
         /// </summary>
         public Type OptionType
@@ -49,7 +49,7 @@ public Type OptionType
         }
 
         /// <summary>
-        /// Gets the instance of <typeparamref cref="TOption"/> described by this 
+        /// Gets the instance of <typeparamref name="TOption"/> described by this
         /// <see cref="OptionDescriptor{TOption}"/>.
         /// </summary>
         public TOption Instance

src/Microsoft.AspNet.Mvc.Core/OptionDescriptors/OutputFormatterDescriptor.cs

@@ -13,7 +13,7 @@ public class OutputFormatterDescriptor : OptionDescriptor<IOutputFormatter>
         /// <summary>
         /// Creates a new instance of <see cref="OutputFormatterDescriptor"/>.
         /// </summary>
-        /// <param name="type">A <see cref="IOutputFormatter/> type that the descriptor represents.
+        /// <param name="type">A <see cref="IOutputFormatter"/> type that the descriptor represents.
         /// </param>
         public OutputFormatterDescriptor([NotNull] Type type)
             : base(type)

src/Microsoft.AspNet.Mvc.Core/OptionDescriptors/ValueProviderFactoryDescriptor.cs

@@ -14,7 +14,7 @@ public class ValueProviderFactoryDescriptor : OptionDescriptor<IValueProviderFac
         /// <summary>
         /// Creates a new instance of <see cref="ValueProviderFactoryDescriptor"/>.
         /// </summary>
-        /// <param name="type">The <see cref="IValueProviderFactory/> type that the descriptor represents.</param>
+        /// <param name="type">The <see cref="IValueProviderFactory"/> type that the descriptor represents.</param>
         public ValueProviderFactoryDescriptor([NotNull] Type type)
             : base(type)
         {

src/Microsoft.AspNet.Mvc.Core/OptionDescriptors/ViewEngineDescriptor.cs

@@ -14,7 +14,7 @@ public class ViewEngineDescriptor : OptionDescriptor<IViewEngine>
         /// <summary>
         /// Creates a new instance of <see cref="ViewEngineDescriptor"/>.
         /// </summary>
-        /// <param name="type">The <see cref="IViewEngine/> type that the descriptor represents.</param>
+        /// <param name="type">The <see cref="IViewEngine"/> type that the descriptor represents.</param>
         public ViewEngineDescriptor([NotNull] Type type)
             : base(type)
         {

src/Microsoft.AspNet.Mvc.Core/Rendering/Html/HtmlHelper.cs

@@ -18,7 +18,7 @@
 namespace Microsoft.AspNet.Mvc.Rendering
 {
     /// <summary>
-    /// Default implementation of non-generic portions of <see cref="IHtmlHelper{T}">.
+    /// Default implementation of non-generic portions of <see cref="IHtmlHelper{TModel}"/>.
     /// </summary>
     public class HtmlHelper : IHtmlHelper, ICanHasViewContext
     {
@@ -125,11 +125,11 @@ public HtmlString ActionLink(
         ///
         /// If the object is already an <see cref="IDictionary{string, object}"/> instance, then it is
         /// returned as-is.
-        /// </summary>
         /// <example>
         /// <c>new { property_name = "value" }</c> will translate to the entry <c>{ "property_name" , "value" }</c>
         /// in the resulting dictionary.
         /// </example>
+        /// </summary>
         /// <param name="obj">The object to be converted.</param>
         /// <returns>The created dictionary of property names and property values.</returns>
         public static IDictionary<string, object> ObjectToDictionary(object obj)
@@ -628,7 +628,7 @@ protected virtual HtmlString GenerateEditor(ModelMetadata metadata, string htmlF
         }
 
         /// <summary>
-        /// Writes an opening <form> tag to the response. When the user submits the form,
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form,
         /// the request will be processed by an action method.
         /// </summary>
         /// <param name="actionName">The name of the action method.</param>
@@ -640,7 +640,9 @@ protected virtual HtmlString GenerateEditor(ModelMetadata metadata, string htmlF
         /// <param name="method">The HTTP method for processing the form, either GET or POST.</param>
         /// <param name="htmlAttributes">An <see cref="IDictionary{string, object}"/> instance containing HTML
         /// attributes to set for the element.</param>
-        /// <returns>An <see cref="MvcForm"/> instance which emits the closing {form} tag when disposed.</returns>
+        /// <returns>
+        /// An <see cref="MvcForm"/> instance which emits the &lt;/form&gt; end tag when disposed.
+        /// </returns>
         protected virtual MvcForm GenerateForm(string actionName, string controllerName, object routeValues,
                                                FormMethod method, IDictionary<string, object> htmlAttributes)
         {

src/Microsoft.AspNet.Mvc.Core/Rendering/HtmlHelperDisplayNameExtensions.cs

@@ -16,7 +16,7 @@ public static class HtmlHelperDisplayNameExtensions
         /// Returns the display name for the current model.
         /// </summary>
         /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
-        /// <returns>A <see langref="string"/> containing the display name.</returns>
+        /// <returns>A <see cref="String"/> containing the display name.</returns>
         public static string DisplayNameForModel([NotNull] this IHtmlHelper htmlHelper)
         {
             return htmlHelper.DisplayName(string.Empty);
@@ -27,12 +27,12 @@ public static string DisplayNameForModel([NotNull] this IHtmlHelper htmlHelper)
         /// if the current model represents a collection.
         /// </summary>
         /// <param name="htmlHelper">
-        /// The <see cref="IHtmlHelper{IEnumerable<TModelItem>}"/> instance this method extends.
+        /// The <see cref="IHtmlHelper{IEnumerable{TModelItem}}"/> instance this method extends.
         /// </param>
         /// <param name="expression">The expression to be evaluated against an item in the current model.</param>
-        /// <typeparam name="TModelItem">The <see cref="Type"/> of items in the model collection.</typeparam>
-        /// <typeparam name="TValue">The <see cref="Type"/> of the <param name="expression"> result.</typeparam>
-        /// <returns>A <see langref="string"/> containing the display name.</returns>
+        /// <typeparam name="TModelItem">The type of items in the model collection.</typeparam>
+        /// <typeparam name="TValue">The type of the <paramref name="expression"/> result.</typeparam>
+        /// <returns>A <see cref="String"/> containing the display name.</returns>
         public static string DisplayNameFor<TModelItem, TValue>(
             [NotNull] this IHtmlHelper<IEnumerable<TModelItem>> htmlHelper,
             [NotNull] Expression<Func<TModelItem, TValue>> expression)

src/Microsoft.AspNet.Mvc.Core/Rendering/HtmlHelperNameExtensions.cs

@@ -12,7 +12,7 @@ public static class HtmlHelperNameExtensions
         /// Returns the full HTML element name for the current model.
         /// </summary>
         /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
-        /// <returns>A <see langref="string"/> containing the element name.</returns>
+        /// <returns>A <see cref="System.String"/> containing the element name.</returns>
         public static string NameForModel([NotNull] this IHtmlHelper htmlHelper)
         {
             return htmlHelper.Name(string.Empty);
@@ -22,7 +22,7 @@ public static string NameForModel([NotNull] this IHtmlHelper htmlHelper)
         /// Returns the HTML element Id for the current model.
         /// </summary>
         /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
-        /// <returns>A <see langref="string"/> containing the element Id.</returns>
+        /// <returns>A <see cref="System.String"/> containing the element Id.</returns>
         public static string IdForModel([NotNull] this IHtmlHelper htmlHelper)
         {
             return htmlHelper.Id(string.Empty);

src/Microsoft.AspNet.Mvc.Core/Rendering/HtmlHelperValueExtensions.cs

@@ -16,9 +16,9 @@ public static class HtmlHelperValueExtensions
         /// </summary>
         /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
         /// <param name="name">Expression name, relative to the current model.</param>
-        /// <returns>A <see langref="string"/> containing the formatted value.</returns>
+        /// <returns>A <see cref="String"/> containing the formatted value.</returns>
         /// <remarks>
-        /// Converts the expression <paramref name="name"/> result to a <see langref="string"/> directly.
+        /// Converts the expression <paramref name="name"/> result to a <see cref="String"/> directly.
         /// </remarks>
         public static string Value([NotNull] this IHtmlHelper htmlHelper, string name)
         {
@@ -30,11 +30,11 @@ public static string Value([NotNull] this IHtmlHelper htmlHelper, string name)
         /// </summary>
         /// <param name="htmlHelper">The <see cref="IHtmlHelper{TModel}"/> instance this method extends.</param>
         /// <param name="expression">The expression to be evaluated against the current model.</param>
-        /// <typeparam name="TModel">The <see cref="Type"/> of the model.</typeparam>
-        /// <typeparam name="TProperty">The <see cref="Type"/> of the <param name="expression"> result.</typeparam>
-        /// <returns>A <see langref="string"/> containing the formatted value.</returns>
+        /// <typeparam name="TModel">The type of the model.</typeparam>
+        /// <typeparam name="TProperty">The type of the <paramref name="expression"/> result.</typeparam>
+        /// <returns>A <see cref="String"/> containing the formatted value.</returns>
         /// <remarks>
-        /// Converts the <paramref name="expression"/> result to a <see langref="string"/> directly.
+        /// Converts the <paramref name="expression"/> result to a <see cref="String"/> directly.
         /// </remarks>
         public static string ValueFor<TModel, TProperty>(
             [NotNull] this IHtmlHelper<TModel> htmlHelper,
@@ -47,9 +47,9 @@ public static string ValueFor<TModel, TProperty>(
         /// Returns the formatted value for the current model.
         /// </summary>
         /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
-        /// <returns>A <see langref="string"/> containing the formatted value.</returns>
+        /// <returns>A <see cref="String"/> containing the formatted value.</returns>
         /// <remarks>
-        /// Converts the model value to a <see langref="string"/> directly.
+        /// Converts the model value to a <see cref="String"/> directly.
         /// </remarks>
         public static string ValueForModel([NotNull] this IHtmlHelper htmlHelper)
         {
@@ -61,12 +61,12 @@ public static string ValueForModel([NotNull] this IHtmlHelper htmlHelper)
         /// </summary>
         /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
         /// <param name="format">
-        /// The composite format <see langref="string"/> (see http://msdn.microsoft.com/en-us/library/txafckwd.aspx).
+        /// The composite format <see cref="String"/> (see http://msdn.microsoft.com/en-us/library/txafckwd.aspx).
         /// </param>
-        /// <returns>A <see langref="string"/> containing the formatted value.</returns>
+        /// <returns>A <see cref="String"/> containing the formatted value.</returns>
         /// <remarks>
-        /// Converts the model value to a <see langref="string"/> directly if
-        /// <paramref name="format"/> is <see langref="null"/> or empty.
+        /// Converts the model value to a <see cref="String"/> directly if
+        /// <paramref name="format"/> is <c>null</c> or empty.
         /// </remarks>
         public static string ValueForModel([NotNull] this IHtmlHelper htmlHelper, string format)
         {