mypy

gh-145966: Fix _csv DIALECT_GETATTR macro silently masking non-Attrib… #20001

Job	Run time
Run mypy on Tools/cases_generator	25s
Run mypy on Tools/check-c-api-docs	25s
Run mypy on Tools/peg_generator	19s
Run mypy on Lib/tomllib	22s
Run mypy on Tools/jit	57s
Run mypy on Tools/build	25s
Run mypy on Tools/clinic	20s
Run mypy on Lib/_pyrepl	24s
Run mypy on Lib/test/libregrtest	19s
	3m 56s

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