Fix clippy lints and bump MSRV to 1.74 #2950

Job	Run time
Deny (advisories)	31s
Clippy	1m 22s
Deny (bans licenses sources)	21s
Check (stable)	1m 1s
Cross (aarch64-linux-android)	2m 17s
Check (1.74.0)	1m 5s
Cross (aarch64-unknown-linux-gnu)	2m 12s
Documentation	58s
Format	18s
Cross (aarch64-unknown-linux-musl)	2m 37s
Hack	1m 44s
Lint markdown files	52s
Tests	4m 8s
Tools	2m 13s
	21m 39s

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