add supplemental-ui to config

wiki-playbook.yml

@@ -16,6 +16,7 @@ ui:
     url: https://github.com/jMonkeyEngine/wiki-ui/releases/latest/download/ui-bundle.zip
     # Required when using cache or fetch will not update ui.
     snapshot: true
+  supplemental_files: ./supplemental-ui    
 asciidoc:
   # Some built-in AsciiDoc attributes are not applicable in the Antora
   # environment. These attributes include data-uri, allow-uri-read, docinfo,