cli: skip formatting instructions if not required #12466

Job	Run time
Build jj-lib without Git support	43s
build (ubuntu-latest)	4m 10s
cargo-deny (advisories)	21s
build (macos-14)	3m 11s
Check protos	25s
cargo-deny (bans licenses sources)	23s
build (windows-latest)	9m 8s
build (ubuntu-latest, --all-features)	5m 16s
Clippy check	2m 29s
Check that MkDocs can build the docs	21s
Check that MkDocs can build the docs with Poetry 1.8	24s
Check formatting	15s
	27m 6s

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