cmds: update the selected filename when running rebase commands

The selected filename can be cleared. Emit a notification so that the
diff editor can update it filename display.

Signed-off-by: David Aguilar <davvid@gmail.com>

cola/cmds.py

@@ -2173,6 +2173,7 @@ def do(self):
         self.model.update_status(update_index=True)
         self.cfg.update()
         self.fsmonitor.refresh()
+        self.selection.selection_changed.emit()
 
 
 class RefreshConfig(ContextCommand):