Experiment: Use rayon when resolving glyphs #1932

Job	Run time
cargo check (aarch64-android)	26s
cargo clippy (windows-latest)	3m 23s
cargo check (msrv) (wasm32)	40s
cargo clippy (macos-latest)	1m 0s
cargo check (msrv) (windows-latest)	1m 46s
cargo clippy (ubuntu-latest)	1m 29s
cargo check (msrv) (macos-latest)	39s
cargo clippy (wasm32)	1m 15s
cargo doc	26s
cargo check (msrv) (ubuntu-latest)	39s
formatting	24s
Prime LFS Cache	4s
cargo test (wasm32)	25s
typos	5s
cargo test (windows-latest)	1m 41s
cargo test (macos-latest)	1m 22s
cargo test (ubuntu-latest)	3m 34s
	19m 18s

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