Remove unused format specifier #4739

Job	Run time
smithay-check-features	3m 3s
format	15s
clippy-check	1m 53s
check-msrv	1m 11s
smallvil-check	55s
anvil-check-features	2m 24s
check-minimal	1m 4s
Documentation on Github Pages	1m 26s
smithay-tests	3m 9s
WLCS: Core tests	1m 24s
WLCS: Output tests	1m 13s
WLCS: Pointer input tests	1m 6s
WLCS: Bad Buffer Test	1m 21s
	20m 24s

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