refactor: remove typing extensions from deps and apply future type hint style

[waketzheng]

Description

Feature:

1. Remove typing_extensions from dependencies list
2. Apply future type hints style

[waketzheng]

• Why remove typing_extensions
  I check py files in aiosqlite/ and docs/ and ensure that typing_extensions is not imported.
• How is type hints improved
  Add from __future__ import annotations to py files in aiosqlite/ that imports typing.
  Then run ruff check --extend-select=UP --ignore=UP031 --fix --unsafe-fixes to auto fix issues.

[amyreese]

I do appreciate you working on this, but I'm going to close this for now. I personally prefer to avoid __future__ annotations, and will keep the 3.9-compatible annotations until I'm ready to drop 3.9 support (after the next release of aiosqlite). typing_extensions has also already been removed in a separate PR. Thank you!