By adding `ui.open-commits=false` in your config, you can now make `jj
checkout` always create a new working-copy commit on top of the
specified commit. If the config is set, open commits will also appear
in the same color as closed commits in `jj log` etc. This will let
some of us experiment with the new UX before we decide if it's a good
idea or not. I left `jj close` in place because it's useful for
setting a description and creating a new commit in one step.
I didn't mention the new config in the release notes because I hope we
can reach a decision and remove the config before the next release.
I'm about to change how `jj checkout` works w.r.t. open/closed commits
(and in particular by moving some logic from the library crate to the
CLI), so let's make sure we have some test coverage.