Fix `clippy::manual_ignore_case_cmp` lint (#229) #754

Job	Run time
cargo clippy (windows-latest)	2m 15s
cargo clippy (macos-latest)	50s
cargo clippy (android) (armv7-linux-androideabi)	53s
cargo clippy (ubuntu-latest)	1m 4s
cargo check (msrv) (windows-latest)	1m 17s
cargo clippy (android) (aarch64-linux-android)	1m 41s
cargo check (msrv) (android) (armv7-linux-androideabi)	29s
cargo check (msrv) (macos-latest)	31s
cargo clippy (android) (x86_64-linux-android)	1m 45s
cargo check (msrv) (ubuntu-latest)	23s
cargo check (msrv) (android) (aarch64-linux-android)	44s
cargo doc (windows-latest)	3m 1s
cargo check (msrv) (android) (x86_64-linux-android)	50s
cargo doc (macos-latest)	57s
formatting	22s
cargo test (windows-latest)	1m 47s
cargo doc (ubuntu-latest)	1m 15s
cargo test (macos-latest)	37s
cargo test (ubuntu-latest)	28s
typos	4s
	21m 13s

Provide feedback