Support for `textDocument/typeDefinition` requests

[jllv]

Feature Request

Out of curiosity I tried to switch from using sumnekos LuaLS for my project over to this language server to compare the user experience. It's really amazing!

One thing I noticed:
As far as I understand it, there is currently no support for textDocument/typeDefinition requests. I think it would be great to have this capability supported by this language server as well.

[CppCXY]

Currently, I am working hard to optimize https://github.com/CppCXY/lua-rs. I hope to focus on these features after I have optimized it to the extreme.