mypy

gh-146197: Add Emscripten to CI #20051

Job	Run time
Run mypy on Tools/peg_generator	18s
Run mypy on Lib/test/libregrtest	19s
Run mypy on Lib/tomllib	20s
Run mypy on Tools/check-c-api-docs	15s
Run mypy on Tools/build	18s
Run mypy on Tools/clinic	19s
Run mypy on Tools/jit	18s
Run mypy on Lib/_pyrepl	19s
Run mypy on Tools/cases_generator	17s
	2m 43s

Provide feedback