cli: remove incorrect help for `jj new`
The help text said you can `jj abandon; jj co to go to the parent
commit (it it's an open commit), but `jj abandon` already takes you to
the parent.
@@ -1385,10 +1385,9 @@ struct AbandonArgs {
/// Create a new, empty change
///
/// This may be useful if you want to make some changes you're unsure of on top
-/// of the working copy. If the changes turned out to useful, you can `jj
+/// of the working copy. If the changes turned out to be useful, you can `jj
/// squash` them into the previous working copy. If they turned out to be
-/// unsuccessful, you can `jj abandon` them and `jj co @-` the previous working
-/// copy.
+/// unsuccessful, you can `jj abandon` them.
#[derive(clap::Args, Clone, Debug)]
struct NewArgs {
/// Parent of the new change
