mypy

gh-134160: Start "Extending and embedding" with a Diataxis-style tuto… #9967

Job	Run time
Run mypy on Tools/build	19s
Run mypy on Lib/tomllib	17s
Run mypy on Lib/_pyrepl	17s
Run mypy on Tools/cases_generator	17s
Run mypy on Lib/test/libregrtest	18s
Run mypy on Tools/clinic	17s
Run mypy on Tools/check-c-api-docs	20s
Run mypy on Tools/peg_generator	21s
Run mypy on Tools/jit	18s
	2m 44s

Provide feedback