Version 2024.04.11:

Updates:

* Change error message hint to suggest `X | None` rather than `Optional[X]`.

Bug fixes:

* Take the 'maybe_missing_members' attribute into account when setting up enum

classes.

* Fix a bug in signature compatibility checking.

* Teach main.py how to fix unescaped spaces in command-line arguments.

* Fix return type of exit() and quit().

* Update pytype_runner.py - change escape_ninja_path to escape all the ninja

path escape-needing characters

* Modify type annotations for coroutines as soon as they are created.

* Fully promote __init_subclass__ to a classmethod.