If a code action provider takes too long to compute a code action during save, we skip that code action. However we do not cancel the request itself

With this change, we now cancel `getCodeActions` when the request times out

fixes #65393

Calling `fire` with zero arguments results in the emitter firing with `undefined`. This is often not expected or desired. It should be explicit that the emitter is fired with undefined

* Manually added strict null checks in around 70 files

* Fixed tsconfig.strictNullChecks.json merge fail

* Touched up a few unnecessary type changes

* Removed files already in other PRs

Code like:

```
private readonly _onDidEncounterLanguage: Emitter<LanguageId> = new Emitter<LanguageId>();
```

Does not need to repeat the `Emitter<LanguageId>` type annotation

- Add toggle action per problem
- Remove global toggle action
- Add commands to show multi or single line