Lint

Bump mypy to 2.0.0 and enable parallel checking #7788

Job	Run time
build (3.14, ubuntu-latest, pre-commit)	1m 0s
build (3.14, windows-latest, pre-commit)	2m 21s
build (3.14, windows-latest, manual)	1m 53s
build (3.14, windows-latest, pre-push)	8m 39s
build (3.14, ubuntu-latest, pre-push)	6m 30s
build (3.14, ubuntu-latest, manual)	54s
completion-lint	3s
	21m 20s

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