Remove duplicate context reference in term definition description.

Author: gkellogg

index.html

@@ -1086,7 +1086,6 @@ <h2>RDF Serialization/Deserialization</h2>
       <li class="changed">an optional <dfn>base URL</dfn> (<a>IRI</a>),</li>
       <li class="changed">an optional <a>context</a> (<a>context</a>),</li>
       <li>an optional <dfn>container mapping</dfn> (<a>array</a> of <a>strings</a>),
-      <li class="changed">an optional <a>context</a> (<a>context</a>),</li>
       <li class="changed">an optional <dfn>direction mapping</dfn> (`"ltr"` or `"rtl"`),</li>
       <li class="changed">an optional <dfn>index mapping</dfn> (<a>string</a>),</li>
       <li>an optional <dfn>language mapping</dfn> (<a>string</a>),</li>