Improvements and cleanup for typing

[maxfischer2781]

This PR is for maintenance on typing support.

• typing bug fixes:
  • ExitStack.push callables now match the proper ... | None instead of just ...
• improved support for matching callables and their parameter types
  • functools.lru_cache preserves method parameters
• promote various (...) -> (await) bool arguments to just (...) -> Any since anything is boolean
• add various missing @overload cases