mypy

gh-150157: Fix critical section for PyDict_Next() in _pickle.c (GH-15… #21669

Job	Run time
Run mypy on Lib/tomllib	20s
Run mypy on Tools/cases_generator	21s
Run mypy on Tools/check-c-api-docs	16s
Run mypy on Tools/build	17s
Run mypy on Tools/clinic	22s
Run mypy on Tools/jit	19s
Run mypy on Lib/test/libregrtest	18s
Run mypy on Lib/_pyrepl	22s
Run mypy on Tools/peg_generator	20s
	2m 55s

Provide feedback