cli: don't hide jj commit from help output

The command is not only useful for new users, it's also useful as a
combination of `jj describe` and `jj new`.

src/commands/mod.rs

@@ -415,7 +415,7 @@ struct DescribeArgs {
 
 /// Update the description and create a new change on top.
 #[derive(clap::Args, Clone, Debug)]
-#[command(hide = true, visible_aliases=&["ci"])]
+#[command(visible_aliases=&["ci"])]
 struct CommitArgs {
     /// The change description to use (don't open editor)
     #[arg(long, short)]