Add c++20 to enums

[Jasdriel]

This are the files in the Typescript part that I found to add the enums, is ok with this changes or there are other parts to update?

For issue #3448.

[sean-mcmanus]

see my other comment

[michelleangela]

Also add "c++20" as another <option> to Config UI in settings.html

And to package.json

[sean-mcmanus]

The msvc version needs to be changed in the .json files: https://github.com/microsoft/vscode-cpptools/blob/master/Extension/bin/msvc.32.intel.json and the other 2 .msvc files.

[sean-mcmanus]

Okay, this seems good, but don't check it in until the C++ side is checked in.

[michelleangela]

Also need to add c++20 to the API https://github.com/microsoft/vscode-cpptools-api. You'll have to create separate pull request on that repo.