[issue45519] Minor docstring improvement in __contains__

Change by Ivan Savov : -- keywords: +patch pull_requests: +27314 stage: -> patch review pull_request: https://github.com/python/cpython/pull/29043 ___ Python tracker ___

[issue45519] Minor docstring improvement in __contains__

New submission from Ivan Savov : Currently, ``` >>> help(list.__contains__) ``` returns ``` Help on wrapper_descriptor: __contains__(self, key, /) Return key in self. ``` Which is a conceptual circular reference, since `in` is implemented by `__contains__`. Changing the help string to