mypy

gh-146197: Add Emscripten to CI #20062

Job	Run time
Run mypy on Tools/cases_generator	22s
Run mypy on Tools/clinic	20s
Run mypy on Tools/peg_generator	20s
Run mypy on Tools/jit	22s
Run mypy on Lib/test/libregrtest	19s
Run mypy on Lib/tomllib	23s
Run mypy on Lib/_pyrepl	20s
Run mypy on Tools/build	18s
Run mypy on Tools/check-c-api-docs	19s
	3m 3s

Provide feedback