Fixed incorrect formatting with private inheritance diagrams

Fixes #195

CHANGELOG.rst

@@ -26,6 +26,9 @@ Bug Fixes
 ^^^^^^^^^
 * `#198 <https://github.com/readthedocs/sphinx-autoapi/issues/198>`:
   Documentation describes the required layout for template override directories.
+* `#195 <https://github.com/readthedocs/sphinx-autoapi/issues/195>`: (Python)
+  Fixed incorrect formatting when ``show-inheritance-diagram``
+  and ``private-members`` are turned on.
 
 Trivial/Internal Changes
 ^^^^^^^^^^^^^^^^^^^^^^^^

autoapi/templates/python/class.rst

@@ -11,7 +11,9 @@
    {% if "show-inheritance-diagram" in autoapi_options and obj.bases != ["object"] %}
    .. autoapi-inheritance-diagram:: {{ obj.obj["full_name"] }}
       :parts: 1
-      {% if "private-members" in autoapi_options %}:private-bases:{% endif %}
+      {% if "private-members" in autoapi_options %}
+      :private-bases:
+      {% endif %}
 
    {% endif %}
    {% endif %}