[Commands Module] Improve usability of type hints (#3410)

* [Commands Module] Better Typehint Support

  We now do a lot more with type hints

  - No more rexporting d.py commands submodules
  - New type aliases for GuildContext & DMContext
  - More things are typehinted

  Note: Some things are still not typed, others are still incorrectly
  typed, This is progress.

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

redbot/core/utils/predicates.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import re
 from typing import Callable, ClassVar, List, Optional, Pattern, Sequence, Tuple, Union, cast