build

cli `new`: Allow `--before/--after` without a value to default to `@` #14628

Job	Run time
Build jj-lib without Git support	52s
build (ubuntu-latest)	4m 20s
build (macos-13)	5m 34s
Check protos	29s
build (macos-14)	5m 54s
Check formatting	17s
build (windows-latest)	10m 6s
build (ubuntu-latest, --all-features)	5m 23s
cargo-deny (advisories)	20s
cargo-deny (bans licenses sources)	21s
Clippy check	2m 29s
Check that MkDocs can build the docs	20s
Check that MkDocs can build the docs with Poetry 1.8	22s
	36m 47s

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