Fix warnings on contract and contractimpl macros (#1344) #4328

Job	Run time
build-fuzz	3m 20s
cargo-deny (advisories)	36s
build-and-test (msrv, ubuntu-latest, x86_64-unknown-linux-gnu)	13m 40s
cargo-deny (bans licenses sources)	35s
check-git-rev-deps	7s
build-and-test (msrv, ubuntu-latest, aarch64-unknown-linux-gnu, true)	8m 35s
build-and-test (msrv, windows-latest, x86_64-pc-windows-msvc)	17m 47s
docs	5m 43s
fmt	5s
build-and-test (latest, ubuntu-latest, x86_64-unknown-linux-gnu)	12m 27s
build-and-test (latest, ubuntu-latest, aarch64-unknown-linux-gnu, true)	7m 29s
build-and-test (latest, windows-latest, x86_64-pc-windows-msvc)	15m 46s
readme	5m 21s
semver-checks	5m 47s
publish-dry-run (ubuntu-latest, wasm32-unknown-unknown) / publish-dry-run / publish-dry-run	8m 1s
publish-dry-run (ubuntu-latest, x86_64-unknown-linux-gnu, --feature-powerset --exclude-features d... / publish-dry-run / publish-dry-run	5m 47s
complete	1s
	1h 51m 7s

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