mypy

gh-139707: Add mechanism for distributors to supply error messages fo… #18201

Job	Run time
Run mypy on Lib/_pyrepl	20s
Run mypy on Tools/cases_generator	18s
Run mypy on Lib/test/libregrtest	25s
Run mypy on Tools/peg_generator	22s
Run mypy on Tools/build	18s
Run mypy on Lib/tomllib	21s
Run mypy on Tools/clinic	18s
Run mypy on Tools/jit	19s
	2m 41s

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