Fix warnings and errors from beta Rust #4733

Job	Run time
cargo-hack	6m 28s
check-docs	41s
check	2m 24s
cargo-public-api-crates (axum)	36s
cargo-deny check (advisories)	26s
dependencies-are-sorted	55s
cargo-public-api-crates (axum-core)	52s
cargo-deny check (bans licenses sources)	1m 1s
Spell Check with Typos	7s
cargo-public-api-crates (axum-extra)	36s
cargo-public-api-crates (axum-macros)	52s
test-msrv	5m 11s
test-nightly	2m 14s
armv5te-unknown-linux-musleabi	1m 10s
test-docs	2m 14s
wasm32-unknown-unknown	40s
test-versions (stable)	3m 42s
test-versions (beta)	3m 48s
	33m 57s

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