* Node-based @deprecated checks
Switch the checker to syntactic checks for `@deprecated` on
declarations. This requires a bit more checking of declarations in the
checker at times, but it
1. Gets rid of work, and a symbol flag, in the binder.
2. Skips work in the checker unless there is a `@deprecated` tag.
3. Makes it fairly simple to only issue errors on particular signatures
of overloaded functions.
* remove in-progress comment
* remove unused isTypeDeclaration
* ❤️ lint
* support jsx and tagged template functions
* Support decorators too
