Enable CSharp Semantic tokens in VSCode

[ryanbrandenburg]

Right now CSharp semantic tokens are not enabled in VSCode because there's no way for use to call through to the CSharp LanguageServer. Other endpoints doing similar things use the vscode.execute<Blank>Provider commands, but no such command exists for Semantic Tokens because it's still a "draft" part of the LSP spec.

[ryanbrandenburg]

VSCode added the API's we need, now available on insiders. microsoft/vscode@f101028

[winstliu]

@NTaylorMullen and Ryan, seeing that VS Code has added the APIs, I'm interested to know how much work you expect wiring up semantic highlighting in VS Code to be, and if it's something you can reasonably see an outside contribution for?
This has caught my eye but want to make sure I won't be stepping on your toes/going in over my head if I were to proceed :).

[ryanbrandenburg]

We're still trying to solidify our current C# semantic token strategy so we aren't fully ready to accept a contribution yet but love that you're digging into the guts of Razor!

[winstliu]

Understandable, thanks for letting me know!

[XorZy]

Any updates?

[davidwengier]

This was fixed in dotnet/vscode-csharp#6489