enable clippy for tower-http and fix current issues #1009

Job	Run time
check-docs	51s
cargo-public-api-crates	1m 5s
check	1m 4s
cargo-hack	2m 23s
cargo-deny check (advisories)	20s
cargo-deny check (bans licenses sources)	31s
test-versions (stable)	3m 32s
test-versions (beta)	1m 50s
style	9s
clippy	49s
test-versions (nightly)	3m 46s
test-msrv	5m 52s
	22m 12s

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