mypy

GH-121970: Remove pyspecific `PyDecoratorMixin` patches (#129306) #582

Job	Run time
Run mypy on Lib/_pyrepl	23s
Run mypy on Lib/test/libregrtest	26s
Run mypy on Tools/build	26s
Run mypy on Tools/cases_generator	21s
Run mypy on Tools/clinic	22s
Run mypy on Tools/jit	27s
Run mypy on Tools/peg_generator	22s
Run mypy on Tools/wasm	22s
	3m 9s

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