Add rename support to the ruby-lsp

[vinistock]

Full support for renaming things, like method names and constants is pretty difficult and should be left for the Sorbet LSP. However, our LSP can support renaming some simple things that don't require complete type checking, like:

• local variables
• method/block/lambda arguments

Remember that our LSP doesn't parse every file in the code base, so our renames are limited to the current file.

Documentation: https://microsoft.github.io/language-server-protocol/specification#textDocument_rename

[andyw8]

I paired with @dirceu to make a start on this:
https://github.com/Shopify/ruby-lsp/compare/andyw8/add-rename-support-for-non-typed-code?expand=1