docs/cli: update URLs to from martinvonz user to jj-vcs org #17162

Job	Run time
build (ubuntu-latest)	5m 20s
Build jj-lib without Git support	1m 1s
build (macos-13)	8m 58s
Check protos	1m 14s
build (macos-14)	4m 36s
build (windows-latest)	12m 58s
build (ubuntu-latest, --all-features)	6m 18s
cargo-deny (advisories)	26s
Check that MkDocs can build the docs	12s
Clippy check	2m 54s
cargo-deny (bans licenses sources)	22s
Check that MkDocs can build the docs with latest Python and uv	10s
Check formatting	17s
	44m 46s

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