609: Allow __enter__() inside an __enter__()

[Dreamsorcerer]

What's wrong

One design pattern is to wrap a context manager. It would be nice to avoid WPS609 errors with this code, which seems to require accessing the direct magic methods.

How it should be

Allow code like:

class Foo:
    ...

    def __enter__(self):
        self._conn.__enter__()
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        self._conn.__exit__(exc_type, exc_value, traceback)

I guess the same for aenter/aexit as well.

[sobolevn]

Yeah, I guess that calling the same magic method inside a magic method is fine.

[lensvol]

If it's not taken, then I could work on this.

[sobolevn]

Just note, that we allow calling all same magic methods. Not just __enter__