Update index.html

Co-authored-by: Pierre-Antoine Champin <github-100614@champin.net>

index.html

@@ -6216,6 +6216,7 @@ <h4>Internal Representation in Implementations</h4>
       </table>
 
       <p>
+      The table below is only provided as an example.
         The mappings used for a particular implementation are out of scope for
         this specification.
       </p>