mypy

Simplify summary tables in the itertools docs (gh-145050) #19616

Job	Run time
Run mypy on Tools/cases_generator	31s
Run mypy on Lib/tomllib	22s
Run mypy on Tools/build	21s
Run mypy on Lib/_pyrepl	18s
Run mypy on Tools/peg_generator	17s
Run mypy on Tools/clinic	21s
Run mypy on Tools/check-c-api-docs	18s
Run mypy on Lib/test/libregrtest	18s
Run mypy on Tools/jit	21s
	3m 7s

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