mypy

GH-145278: freeze encodings (partially) and linecache (#145279) #19829

Job	Run time
Run mypy on Lib/_pyrepl	16s
Run mypy on Tools/cases_generator	20s
Run mypy on Tools/build	22s
Run mypy on Tools/clinic	17s
Run mypy on Tools/check-c-api-docs	17s
Run mypy on Tools/jit	17s
Run mypy on Tools/peg_generator	20s
Run mypy on Lib/tomllib	22s
Run mypy on Lib/test/libregrtest	20s
	2m 51s

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