Merge typeshed return annotations #5913

Job	Run time
test_cygwin (39, windows-latest)	18m 53s
collateral (diffcov)	5m 36s
test (3.9, ubuntu-latest)	4m 7s
collateral (docs)	2m 9s
test (3.9, macos-latest)	3m 52s
test (3.9, windows-latest)	3m 59s
test (3.13, ubuntu-latest)	4m 8s
test (3.13, macos-latest)	4m 10s
test (3.13, windows-latest)	3m 59s
test (3.10, ubuntu-latest)	3m 52s
test (3.11, ubuntu-latest)	3m 52s
test (3.12, ubuntu-latest)	4m 8s
test (3.14, ubuntu-latest)	4m 7s
test (pypy3.10, ubuntu-latest, stdlib)	4m 6s
test (ubuntu-latest, 3.10, stdlib)	4m 6s
integration-test	0s
check	2s
release	1s
	1h 15m 7s

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