message: Remove invalid interfacename attribute
  This changelist removes an invalid interfacename attribute from the nodegraph_nodegraph example, allowing improvements to document validation logic in the future.
diff: <!-- Nodegraph to node connection -->
  <image name="upstream_image" type="color3">
  - <input name="file" type="filename" interfacename="file" value="resources/Images/cloth.png" />
  + <input name="file" type="filename" value="resources/Images/cloth.png" />
  </image>
  <nodegraph name="graph_to_node">
  <input name="input" type="color3" nodename="upstream_image" value="0, 1, 0" />
  