cli: hide jj close/commit and jj open/uncommit

Now that open commits are disabled by default, seeing `close` and
`open` in `jj help` is confusing.

I'm a little ambivalent about hiding `jj commit` because it's useful
as a way of adding a description and starting a new change with a
single command. We can always add a new command for that if we want
to.

src/commands.rs

@@ -1421,7 +1421,7 @@ struct DescribeArgs {
 /// For information about open/closed revisions, see
 /// https://github.com/martinvonz/jj/blob/main/docs/working-copy.md.
 #[derive(clap::Args, Clone, Debug)]
-#[clap(visible_alias = "commit")]
+#[clap(visible_alias = "commit", hide = true)]
 struct CloseArgs {
     /// The revision to close
     #[clap(default_value = "@")]
@@ -1442,7 +1442,7 @@ struct CloseArgs {
 /// For information about open/closed revisions,
 /// see https://github.com/martinvonz/jj/blob/main/docs/working-copy.md.
 #[derive(clap::Args, Clone, Debug)]
-#[clap(visible_alias = "uncommit")]
+#[clap(alias = "uncommit", hide = true)]
 struct OpenArgs {
     /// The revision to open
     revision: String,