Add rename feature #22
Description
Problem(s) this feature will solve
Add the ability to rename an entity
Describe the solution you'd like
Implement the following in userver:
https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_rename
Implementation details:
- Make a internal headless API to refactor rename, pulling out the reference logic from the existing GUI API. The GUI refactor tool and userver should both use these references.