mypy

gh-143008: Fix Null pointer dereferences in TextIOWrapper underlying … #21783

Job	Run time
Run mypy on Lib/tomllib	18s
Run mypy on Lib/test/libregrtest	19s
Run mypy on Tools/jit	19s
Run mypy on Tools/peg_generator	19s
Run mypy on Lib/_pyrepl	19s
Run mypy on Tools/cases_generator	16s
Run mypy on Tools/clinic	20s
Run mypy on Tools/build	18s
Run mypy on Tools/check-c-api-docs	18s
	2m 46s

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