Update stable Rust, fix clippy lints (#404) #726

Job	Run time
cargo test (windows-latest)	58s
cargo clippy (wasm32)	1m 22s
cargo test (macos-latest)	42s
cargo check (msrv) (windows-latest)	2m 3s
cargo test (ubuntu-latest)	31s
cargo check (msrv) (wasm32)	1m 9s
cargo check (msrv) (macos-latest)	1m 14s
cargo check (msrv) (ubuntu-latest)	1m 16s
cargo clippy (windows-latest)	1m 57s
cargo doc	22s
formatting	39s
cargo test (wasm32)	36s
typos	3s
cargo clippy (macos-latest)	1m 3s
cargo clippy (ubuntu-latest)	1m 13s
	15m 8s

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