Improve wording in _Serialize RDF as JSON-LD_ to ensure that _node_ is a bnode while in loop.

Fixes #493.

Author: gkellogg

spec/latest/json-ld-api/index.html

@@ -3102,7 +3102,7 @@ <h3>Algorithm</h3>
                       equal if they have equivalent key-value pairs.</li>
                   </ol>
                 </li>
-                <li>Otherwise, append <em>reference</em> to the <code>@list</code> member of <em>list</em>.</li>
+                <li>Otherwise, append <em class="changed">reference</em> to the <code>@list</code> member of <em>list</em>.</li>
               </ol>
             </li>
             <li>If <em>element</em> has an <code>@type</code> key, append
@@ -3657,6 +3657,8 @@ <h2>Algorithm</h2>
                 <li>Initialize two empty <a>arrays</a> <em>list</em>
                   and <em>list nodes</em>.</li>
                 <li>While <em>property</em> equals <code>rdf:rest</code>,
+                  <span class="changed">the value of the <code>@id</code> member
+                    of <em>node</em> is a <a>blank node identifier</a>,</span>
                   the <a>array</a> value of the member of <em>node usages map</em> associated with the <code>@id</code>
                   member of <code>node</code> has only one member,
                   <span class="changed">