mypy

gh-140281: Update free threading Python HOWTO for 3.14 (gh-140566) #18211

Job	Run time
Run mypy on Lib/tomllib	19s
Run mypy on Lib/_pyrepl	20s
Run mypy on Lib/test/libregrtest	20s
Run mypy on Tools/cases_generator	17s
Run mypy on Tools/clinic	22s
Run mypy on Tools/peg_generator	20s
Run mypy on Tools/build	20s
Run mypy on Tools/jit	21s
	2m 39s

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