Clamp alpha during parse, other tweaks #425

Job	Run time
cargo clippy (windows-latest)	52s
cargo check (msrv) (windows-latest)	36s
cargo clippy (macos-latest)	29s
cargo check (msrv) (macos-latest)	21s
cargo clippy (ubuntu-latest)	26s
cargo check (msrv) (ubuntu-latest)	18s
cargo clippy (wasm32)	37s
cargo doc	16s
formatting	21s
cargo miri	1m 32s
cargo check (msrv) (wasm32)	15s
cargo test (windows-latest)	40s
cargo test (wasm32)	18s
cargo test (macos-latest)	24s
typos	6s
cargo test (ubuntu-latest)	15s
	7m 46s

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