Remove .gitignore #4781

Job	Run time
test_cygwin (39, windows-latest)	16m 54s
test (3.8, ubuntu-latest)	3m 42s
collateral (diffcov)	5m 37s
test (3.8, windows-latest)	11m 0s
collateral (docs)	1m 58s
test (3.12, ubuntu-latest)	5m 34s
collateral (check-extern)	9s
test (3.12, macos-latest)	4m 3s
test (3.12, windows-latest)	11m 36s
test (3.9, ubuntu-latest)	4m 6s
test (3.10, ubuntu-latest)	3m 45s
test (3.11, ubuntu-latest)	4m 2s
test (pypy3.10, ubuntu-latest, stdlib)	15m 7s
test (ubuntu-latest, 3.10, stdlib)	3m 42s
test (3.8, macos-13)	7m 20s
integration-test	0s
check	3s
release	0s
	1h 38m 38s

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