RET501 should exempt overriding class methods

[epenet]

If a parent class defines a return type hint for a method, then it makes sense to keep the return None explicit.
This is similar to #3704/#3705, but it involves looking also at the parent classes.

class BaseClass:
    def get_value(self) -> str | None:
        return "a value"

class Class(BaseClass):
    def get_value(self) -> None:
        return None
        # RET501 [*] Do not explicitly `return None` in function if it is the only possible return value

Based on home-assistant/core#115031

[AlexWaygood]

This seems reasonable to me. PR welcome.

[epenet]

Note: it appears this would be severely limited by the multifile-analysis restrictions.
#7447

[MichaReiser]

Yes, this is a good point. I don't think we can implement this today without multifile-analysis

[Avasam]

With the @override decorator this can be done w/o multi-fine analysis.