Generate csharp.tmLanguage.yml using Roslyn

[am11]

A tool was introduced to write Antlr grammar: https://github.com/dotnet/roslyn/tree/5cae62a/src/Tools/Source/CompilerGeneratorTools/Source/CSharpSyntaxGenerator.

The result is: https://github.com/dotnet/roslyn/blob/5cae62a/src/Compilers/CSharp/Portable/Generated/CSharp.Generated.g4.

I think it would save some effort to support future versions of language, if the textmate grammar generation is also done by tool like CSharpSyntaxGenerator.

[CyrusNajmabadi]

if the textmate grammar generation is also done by tool like CSharpSyntaxGenerator.

I don't think Roslyn needs to be in the business of doing this. TextMate (or some interested party) can use the same information that Roslyn uses to generate the appropriate files it needs.