ctutils: additional clippy lints (#1384) #1162

Job	Run time
x86 (x86_64-unknown-linux-gnu, stable)	21s
test-derive (stable)	29s
cross (aarch64-unknown-linux-gnu, stable)	44s
cross (powerpc-unknown-linux-gnu, stable)	40s
x86 (x86_64-unknown-linux-gnu, 1.85.0)	22s
build (stable, wasm32-unknown-unknown)	18s
build (stable, thumbv7em-none-eabi)	17s
build (1.85.0, wasm32-unknown-unknown)	15s
minimal-versions / minimal-versions	1m 2s
cross (powerpc-unknown-linux-gnu, 1.85.0)	40s
build (stable, armv7a-none-eabi)	16s
test (i686-unknown-linux-gnu, ubuntu-latest, 1.85.0, sudo apt update && sudo apt install gcc-mult...	31s
build (1.85.0, armv7a-none-eabi)	16s
test (x86_64-apple-darwin, macos-latest, stable)	17s
build (1.85.0, thumbv7em-none-eabi)	15s
test (x86_64-unknown-linux-gnu, ubuntu-latest, 1.85.0)	17s
test (x86_64-pc-windows-msvc, windows-latest, stable)	41s
cross (aarch64-unknown-linux-gnu, 1.85.0)	45s
test (x86_64-unknown-linux-gnu, ubuntu-latest, stable)	25s
test (x86_64-pc-windows-msvc, windows-latest, 1.85.0)	34s
test (i686-unknown-linux-gnu, ubuntu-latest, stable, sudo apt update && sudo apt install gcc-mult...	35s
test (x86_64-apple-darwin, macos-latest, 1.85.0)	20s
test-derive (1.85.0)	27s
	10m 47s

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