Fix closing HTML tag.

Author: gkellogg

index.html

@@ -10875,7 +10875,7 @@ <h3>Graph Containers</h3>
     to be used in place of the originally requested resource,
     as described in <a href="#alternate-document-location" class="sectionRef"></a>.</p>
 
-<section class="normative"><h3>Interpreting JSON as JSON-LD</h2>
+<section class="normative"><h3>Interpreting JSON as JSON-LD</h3>
 
   <p>Ordinary JSON documents can be interpreted as JSON-LD
     by providing an explicit JSON-LD <a>context</a> document. One way