re-insert floating cons next to the currently focused con of the appropriate workspace

include/con.h

@@ -152,6 +152,14 @@ Con *con_next_focused(Con *con);
  */
 Con *con_get_next(Con *con, char way, orientation_t orientation);
 
+/**
+ * Returns the focused con inside this client, descending the tree as far as
+ * possible. This comes in handy when attaching a con to a workspace at the
+ * currently focused position, for example.
+ *
+ */
+Con *con_descend_focused(Con *con);
+
 /**
  * Returns a "relative" Rect which contains the amount of pixels that need to
  * be added to the original Rect to get the final position (obviously the