mypy

gh-145883: Fix two heap-buffer-overflows in `_zoneinfo` #20023

Job	Run time
Run mypy on Lib/tomllib	1m 27s
Run mypy on Tools/check-c-api-docs	17s
Run mypy on Tools/build	53s
Run mypy on Tools/peg_generator	21s
Run mypy on Lib/_pyrepl	17s
Run mypy on Tools/cases_generator	20s
Run mypy on Tools/clinic	19s
Run mypy on Tools/jit	19s
Run mypy on Lib/test/libregrtest	18s
	4m 31s

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