@react macro annotation for Scala 3.5.0

[steinybot]

It looks like macro annotations can now modify their companion objects in Scala 3.5.0: scala/scala3#19677

[steinybot]

Wait a minute... why was I thinking that this needs to go on the props class?

[steinybot]

The best solution I can think of which has the fewest breaking changes is to:

1. Add a scalafix rule which rewrites objects with @react annotations to:
   1. Extract the Props to a companion case class.
   2. Add a parent trait to the object for which a @react macro annotation can implement.
2. The parent trait defines an abstract given Conversion[Props, KeyAddingStage] (and possibly others to avoid having to chain implicits)
3. The @react macro annotation implements the given Conversion[Props, KeyAddingStage] using the component.

The exact shape of the props companion case class and member to implement in the companion object needs a bit more thought but this is the basic idea.