mypy

Add Diego as author of PEP 831 (#149551) #21235

Job	Run time
Run mypy on Tools/jit	36s
Run mypy on Tools/peg_generator	34s
Run mypy on Lib/test/libregrtest	30s
Run mypy on Lib/_pyrepl	31s
Run mypy on Tools/check-c-api-docs	28s
Run mypy on Tools/clinic	32s
Run mypy on Tools/build	26s
Run mypy on Tools/cases_generator	28s
Run mypy on Lib/tomllib	28s
	4m 33s

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