$ git reset --keep start <3>
------------
+
<1> This commits your first edits in `branch1`.
<2> In the ideal world, you could have realized that the earlier
commit did not belong to the new topic when you created and switched
$ git reset --keep start <3>
------------
+
<1> This commits your first edits in `branch1`.
<2> In the ideal world, you could have realized that the earlier
commit did not belong to the new topic when you created and switched