Switch to use a more explicit, more state-machine like approach to states for code actions

Replace all void 0 with undefined

Update copyright year to 2019

Define less fonts

See https://github.com/Microsoft/TypeScript-TmLanguage/issues/691

Assuming that properties named `label` or `name` are dom properties is incorrect and causes a lot of false positives. This results in weirdly inconsistent colorization

* strictNullChecks for macLinuxKeyboardMapper

* Fix strict null check for assertResolveUserBinding

* Add comma

Fixes #65513

Fixes #65504

Fixes #65733