lsp: Add partial support for insert/replace completions (#9634)

Most notably, this should do away with completions overriding the whole
word around completion trigger text. Fixes: #4816



Release Notes:

- Fixed code completions overriding text around the cursor.
e20508f66cPiotr Osiewicz committed on 3/21/2024, 3:19:21 PM· committed by GitHubparent6184278
2 files changedLine totals unavailable