mypy

gh-144001: Support ignorechars in binascii.a2b_base64() and base64.b6… #19284

Job	Run time
Run mypy on Lib/test/libregrtest	23s
Run mypy on Lib/_pyrepl	18s
Run mypy on Tools/clinic	21s
Run mypy on Tools/jit	22s
Run mypy on Tools/check-c-api-docs	18s
Run mypy on Tools/build	19s
Run mypy on Tools/cases_generator	25s
Run mypy on Lib/tomllib	18s
Run mypy on Tools/peg_generator	18s
	3m 2s

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