LSP Refactoring Capabilities

[xeho91]

What Am I Proposing?

Add refactoring code actions to the typescript@7 LSP.

Why?

Modern IDEs (such as VS Code, Neovim, and Zed) rely on refactoring code actions as a core part of the TypeScript editing experience.
Without these refactoring actions, the typescript@7 LSP feels incomplete compared to vtsls / typescript-language-server.
Users migrating to this newer version lose these workflows.

Refactoring Actions Tracker

Verified against VS Code TypeScript refactoring docs and TypeScript source.

• Add/remove braces from arrow function source
• Convert between arrow function and function expression source
• Convert between default export and named export source
• Convert between named imports and namespace imports source
• Convert between string and template literal source
• Convert overload list to single signature source
• Convert to optional chain expression source
• Convert parameters to destructured object source
  • ⚠️ Likely won't be ported Port Convert parameters to destructed object refactoring #2281
• Extract function source
• Extract type source
• Extract variable source
• Generate get and set accessors source
• Infer function return type source
  • Add Infer function return type refactoring code action #4749
• Inline variable source
• Move to new file source
  • Interactive code actions (like "Move to file") #2468