fix element refs

Author: arottier

dom.bs

@@ -3407,10 +3407,10 @@ dictionary MutationObserverInit {
    to the presence of an elements <a>attributes</a>.
 
    <dt>{{MutationObserverInit/elementLocalNameFilter}}
-   <dd>Set to a list of <a>element</a>
+   <dd>Set to a list of <a for=/>element</a>
    <a for=Element>local names</a> (without <a for=Attr>namespace</a>) to observe
    changes to the presence of specific <a>element</a> <a for=Element>local names</a>
-   if not all <a>element</a> <a for=Element>local names</a> need to be
+   if not all <a for=/>element</a> <a for=Element>local names</a> need to be
    observed and {{MutationObserverInit/attributes}} is true
    or omitted.
   </dl>