build

refactor: Roll our own hex utils #14579

Job	Run time
Build jj-lib without Git support	47s
build (ubuntu-latest)	4m 23s
Check protos	23s
Clippy check	2m 29s
build (macos-13)	9m 10s
cargo-deny (advisories)	23s
cargo-deny (bans licenses sources)	21s
build (macos-14)	3m 20s
build (windows-latest)	9m 48s
Check that MkDocs can build the docs	21s
Check that MkDocs can build the docs with Poetry 1.8	21s
build (ubuntu-latest, --all-features)	5m 16s
Check formatting	16s
	37m 18s

Provide feedback