mypy

gh-139533: fix refs to code without proper markups on turtledemo doc … #17843

Job	Run time
Run mypy on Lib/test/libregrtest	20s
Run mypy on Tools/jit	17s
Run mypy on Tools/peg_generator	19s
Run mypy on Lib/tomllib	15s
Run mypy on Lib/_pyrepl	20s
Run mypy on Tools/cases_generator	17s
Run mypy on Tools/clinic	18s
Run mypy on Tools/build	19s
	2m 25s

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