Fix build warnings under rustc 1.75.0 #20909

Job	Run time
linting	2m 23s
rustfmt	14s
ext-test	5m 23s
build (self-hosted, beta)	2h 2m 1s
build (self-hosted, stable)	2h 2m 5s
build (self-hosted, 1.75.0)	1h 19m 59s
build (macos-latest, stable)	1h 51m 6s
build (windows-latest, stable)	2h 21m 34s
build (macos-latest, 1.75.0)	2h 11m 12s
check_release	2m 56s
build-tx-sync (macos-latest, stable)	7m 59s
build-tx-sync (ubuntu-latest, stable)	4m 50s
benchmark	17m 19s
check_docs	4m 11s
build-tx-sync (macos-latest, beta)	7m 1s
build-tx-sync (ubuntu-latest, beta)	4m 48s
build-tx-sync (macos-latest, 1.75.0)	8m 46s
fuzz	1h 30m 31s
build-tx-sync (ubuntu-latest, 1.75.0)	5m 26s
coverage	22m 30s
	14h 52m 14s

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