Fixes #80118

add CompletionOptions with support to filter by completion kind. Will make it simple to implement #45039

* 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

We set alwaysStrict so this directive is not needed

debt - remove suggest adapter and use CompletionItemProvider from modes.ts. Also fixes https://github.com/Microsoft/monaco-editor/issues/985

Standardizing syntax and discouraging use of `this` inside tests

when the 'query' string is getting longer it's save to score afore scored/filtered items only, #15419