[css3-fonts] fix link error

Author: John Daggett

css3-fonts/Overview.html

@@ -4391,8 +4391,9 @@ <h3 id=font-feature-values><span class=secno>6.9 </span>Defining font
   font-variant-alternates: character-variant(zeta-2, zeta);
 }</pre>
 
-  <p>See <a href="#font-feature-values-DOM">Appendix B</a> for a description
-   of the interfaces used to modify these rules via the CSS Object Model.
+  <p>See the <a href="#om-fontfeaturevalues">object model reference
+   section</a> for a description of the interfaces used to modify these rules
+   via the CSS Object Model.
 
   <div class=figure><img alt="Matching text on Byzantine seals using
    character variants" src=byzantineseal.png>