docs: mention `jj rebase -b` in git-comparison doc
I forgot to update the document in
@@ -199,8 +199,7 @@ parent.
</tr>
<tr>
<td>Move branch A onto branch B</td>
- <td>Not supported yet (can be emulated with
- <code>jj rebase -s</code>)</td>
+ <td><code>jj rebase -b A -d B</code></td>
<td><code>git rebase B A</code>
(may need to rebase other descendant branches separately)</td>
</tr>
