mypy

876f6361 - Improve support for functools.partial of overloaded callable protocol (#18639)

Improve support for functools.partial of overloaded callable protocol (#18639) Resolves #18637 Mypy's behaviour here is not correct (see test case), but this PR makes mypy's behaviour match what it used to be before we added the functools.partial plugin Support for overloads tracked in #17585