Allow Razor logs to be directed to the right output window in VS Code

[davidwengier]

In VS Code, Razor cohosting logs to the Razor Log output category as you would expect, but all of the CLaSP logging ends up in the C# output, including all of the MEF composition and ALC processing stuff, which is relatively noisy. This fixes that by remapping logs to the Razor log endpoint for contexts that specify the Razor language, and makes requests for Razor specify that context.

This is a bit of speculative work on a Sunday, so feel free to reject or suggest a different API. I don't really love having a separate method for this, but having one method with two parameters would mean nobody ever passes in both parameters.

The results at runtime in VS Code are huge though, and will make investigating issues easier for us and you.

Part of dotnet/razor#11759

[davidwengier]

I guess the other option here would be to use a custom Roslyn log message handler that passed along language info, and do the redirection there, but I think the ILspLogger changes would be the same.

[dibarbet]

this seems fine. an alternative path might be to utilize the same LSP message, but add on an additional language property. Then on the client via a middleware, redirect to the Razor logger.

But I am fine with either approach, I can't think of meaningful differences between them

[davidwengier]

Then on the client via a middleware

Had the same thought, but window/log is not middleware-able: microsoft/vscode-languageserver-node#1131

[dibarbet]

Had the same thought, but window/log is not middleware-able: microsoft/vscode-languageserver-node#1131

that makes the choice easy then!