DOC: Fix inheritance diagram [ci skip]

pllim · pllim · commit debe04eb7894 · 2021-02-23T11:21:55.000-05:00
diff --git a/docs/ginga.rst b/docs/ginga.rst
@@ -93,6 +93,7 @@ API
 .. automodule:: astrowidgets.ginga
 
 .. inheritance-diagram:: astrowidgets.ginga.ImageWidget
+    :top-classes: ipywidgets.VBox
 
 .. autoclass:: astrowidgets.ginga.ImageWidget
     :members:
