tests

Remove unused vars or mark them explicitly #1149

Job	Run time
test_cygwin (39, windows-latest)	17m 46s
collateral (diffcov)	5m 23s
collateral (docs)	1m 53s
test (3.9, ubuntu-latest)	4m 28s
test (3.9, macos-latest)	4m 21s
test (3.9, windows-latest)	10m 35s
test (3.13, ubuntu-latest)	5m 11s
test (3.13, macos-latest)	4m 18s
test (3.13, windows-latest)	12m 17s
test (3.10, ubuntu-latest)	4m 14s
test (3.11, ubuntu-latest)	3m 59s
test (3.12, ubuntu-latest)	5m 29s
test (3.14, ubuntu-latest)	6m 32s
test (pypy3.10, ubuntu-latest, stdlib)	16m 3s
test (ubuntu-latest, 3.10, stdlib)	4m 14s
integration-test	0s
check	2s
release	0s
	1h 46m 45s

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