mypy

gh-119494: Fix error messages for deleting/setting type attributes (#… #16852

Job	Run time
Run mypy on Tools/build	19s
Run mypy on Lib/test/libregrtest	17s
Run mypy on Tools/peg_generator	20s
Run mypy on Lib/tomllib	21s
Run mypy on Tools/jit	24s
Run mypy on Lib/_pyrepl	19s
Run mypy on Tools/cases_generator	22s
Run mypy on Tools/clinic	22s
	2m 44s

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