Q/codewhisperer does not support LSP standard "textDocument/completion" method

[justinmk3]

Problem

The LSP standard textDocument/completion method is not supported. Inline suggestions are currently provided by the custom aws/textDocument/inlineCompletion[WithReferences] method(s).

• https://github.com/aws/language-server-runtimes/blob/0cb2bfe5036884661cd7a5c8d0f68252db81ea64/runtimes/protocol/inlineCompletions.ts
• https://github.com/aws/language-server-runtimes/blob/0cb2bfe5036884661cd7a5c8d0f68252db81ea64/runtimes/protocol/inlineCompletionWithReferences.ts

This means that:

• LSP clients have to build custom integration just to get suggestions from the Amazon Q LSP, even though that is a standard feature of LSP.
• in clients like Nvim or Emacs, every completion plugin must also be manually integrated.

Expected behavior

Inline suggestions should be exposed from the standard LSP textDocument/completion (and related) methods, where possible. At least in some minimal/degraded form, if it's not possible to provide the full features.