doc string tweak

Author: jchanvfx

NodeGraphQt/base/graph.py

@@ -829,6 +829,9 @@ def set_layout_direction(self, direction):
             * :attr:`NodeGraphQt.constants.LayoutDirectionEnum.HORIZONTAL`
             * :attr:`NodeGraphQt.constants.LayoutDirectionEnum.VERTICAL`
 
+            .. image:: _images/layout_direction_switch.gif
+                :width: 300px
+
         Warnings:
             This function does not register to the undo stack.