typescript: Complete function calls with snippets (#11157)

This allows function call (i.e. snippet) completion with
`typescript-language-server`. So far that didn't work, because
`typescript-language-server` doesn't respond with `insertText` when
getting the completions, but only when then sending
`completionItem/resolve` requests. See:
https://github.com/hrsh7th/nvim-cmp/issues/646#issuecomment-992765479

What this PR does is to support text edits in the response to
`completionItem/resolve`, which means updating the completion item.

It then enables this feature by default for
`typescript-language-server`.


TODOs:

- [x] Make this work over collab
- [x] Test that this doesn't break existing language server support
- [x] Refactor duplicated code

Release Notes:

- Added support for function call completion when using
`typescript-language-server`. This will result in parameters being
added, which can then be changed and navigated with `<tab>`. For this to
work with `typescript-language-server`, the documentation for a given
completion item needs to be resolved, meaning that if one types very
quickly and accepts completion before `typescript-language-server` could
respond with the documentation, no full function completion is used.

Demo:


https://github.com/zed-industries/zed/assets/1185253/c23ebe12-5902-4b50-888c-d9b8cd32965d

crates/rpc/proto/zed.proto

@@ -1024,15 +1024,22 @@ message ResolveState {
     }
 }
 
+// This type is used to resolve more than just
+// the documentation, but for backwards-compatibility
+// reasons we can't rename the type.
 message ResolveCompletionDocumentation {
     uint64 project_id = 1;
     uint64 language_server_id = 2;
     bytes lsp_completion = 3;
+    uint64 buffer_id = 4;
 }
 
 message ResolveCompletionDocumentationResponse {
-    string text = 1;
-    bool is_markdown = 2;
+    string documentation = 1;
+    bool documentation_is_markdown = 2;
+    Anchor old_start = 3;
+    Anchor old_end = 4;
+    string new_text = 5;
 }
 
 message ResolveInlayHint {