* Initial work on signature help context

Fixes #54972

Adds `SignatureHelpContext`. This tells providers why signature help was requested

TODO:

- [ ] Better understand semantics of retrigger. Should `retrigger` be an flag instead of a `triggerReason`?
- [ ]  Fix skipped test
- [ ] Add more tests for trigger reasons / trigger characters

* Fix unit test

* Make sure we retrigger sig help if it is already showing

* Add test for dismiss and re-invoke

* Extract some constants

* Extract createMockEditor

Changes how jsdoc completion works to reduce typing delays and hopefully avoid showing it for fewer false positives. Main changes

- Only show the completion item if typescript's docCommentTemplate returns something. This means that you won't see the completion item in cases like: `/** |a */`  or `/**|` anymore. However in the case of `/**|`, pressing return will still complete to the empty comment as expected

- Get the snippet for the completion early so there is no flash when accepting it

Bring this setting name inline with other suggestions settings

Part of #58385

The new  `javascript.suggest.paths` and `typescript.suggest.paths` settings replace `typescript.quickSuggestionsForPaths`. These settings should disable all path based suggestions from js/ts

The old `quickSuggestionsForPath` setting is now marked deprecated and is not being migrated to these new settings as it has different semantics. It was originally designed just to disable quick suggestions for paths but it does not work properly when using TypeScript 2.9+

Part of #58385

Rename `typescript.suggestions.enabled` to `typescript.suggest.enabled` to be more consistent with other extensions

Fix #57250. Do not do any auto closing check/update if the cursor is before an closing brace in composition mode.

* New config to turn off TypeScript autocomplete suggestions

* add missing semicolon

* Exclude everything, even name suggestions, when suggestions disabled

Fixes #55700

- Add commit characters for keywords such as `this` and `super`.
- Allow trigger characters on lines with only leading whitespace

Fixes #58048

Fixes #58256