mypy

Revert "gh-143050: Remove redundant decref in _PyLong_Negate (gh-1430… #19920

Job	Run time
Run mypy on Tools/cases_generator	17s
Run mypy on Tools/check-c-api-docs	17s
Run mypy on Lib/_pyrepl	20s
Run mypy on Lib/tomllib	17s
Run mypy on Tools/jit	18s
Run mypy on Tools/build	18s
Run mypy on Lib/test/libregrtest	19s
Run mypy on Tools/peg_generator	21s
Run mypy on Tools/clinic	18s
	2m 45s

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