Colorize text in FSharpDiagnostics

I propose we use tagged texts in errors/warnings produced by FCS. Below are examples of how it looks for C# in Rider, and it would be nice to do this for F# as well.

Here's a qualified name:

And here's a short name of a method:

It seems especially useful when (longer) signatures are presented (in overload resolution, missing overrides, etc):

This may also be a good community-driven initiative, since it's possible to make separate pull requests for different diagnostics.