LSP support for Carbon

[shrkamat]

It will be great if a Language Server can be made available for Carbon. It can greatly help in adoption of the language.

[robiot]

+1 As stated in the project goals under Language tools and ecosystem goals

Developer tooling. We need developers to be productive reading and writing Carbon code. We expect to provide a broad suite of development oriented tools ranging from refactoring tools to LSP implementations and editor integrations. We also plan to provide machine readable forms of many parts of the language, such as a grammar, to ensure consistency between tools and enable the development of tools by others.

https://github.com/carbon-language/carbon-lang/blob/trunk/docs/project/goals.md

But it's nice having an issue to point out this project goal specifically.

[JVApen]

Seems there was progress, see #3169