mypy

gh-139707: Add mechanism for distributors to supply error messages for missing stdlib modules #18167

Job	Run time
Run mypy on Lib/tomllib	17s
Run mypy on Lib/_pyrepl	17s
Run mypy on Tools/peg_generator	19s
Run mypy on Tools/jit	17s
Run mypy on Tools/build	19s
Run mypy on Tools/cases_generator	17s
Run mypy on Lib/test/libregrtest	22s
Run mypy on Tools/clinic	18s
	2m 26s

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