mypy

gh-146636: PEP 803: Reference documentation #20374

Job	Run time
Run mypy on Lib/test/libregrtest	17s
Run mypy on Tools/jit	19s
Run mypy on Tools/build	18s
Run mypy on Tools/cases_generator	21s
Run mypy on Tools/check-c-api-docs	17s
Run mypy on Lib/tomllib	18s
Run mypy on Tools/clinic	17s
Run mypy on Lib/_pyrepl	17s
Run mypy on Tools/peg_generator	16s
	2m 40s

Provide feedback