added missing keywords in step 28 (Create Term Definition)

Author: pchampin

index.html

@@ -1839,11 +1839,17 @@ <h3>Algorithm</h3>
               has been detected and processing is aborted.</li>
           </ol>
         </li>
-        <li>If the value contains any <a>entry</a> other than <code>@id</code>,
+        <li id="ctd-invalid-entries">If the value contains any <a>entry</a> other than <code>@id</code>,
           <code>@reverse</code>, <code>@container</code>,
-          <code class="changed">@context</code>, <code>@language</code>, <code class="changed">@nest</code>,
-          <code class="changed">@prefix</code>, or <code>@type</code>, an
-          <a data-link-for="JsonLdErrorCode">invalid term definition</a> error has
+          <code class="changed">@context</code>, 
+          <code class="changed">@direction</code>,
+          <code class="changed">@index</code>,
+          <code>@language</code>,
+          <code class="changed">@nest</code>,
+          <code class="changed">@prefix</code>,
+          <code class="changed">@protected</code>,
+          or <code>@type</code>,
+          an <a data-link-for="JsonLdErrorCode">invalid term definition</a> error has
           been detected and processing is aborted.</li>
         <li class="changed">If <var>override protected</var> is <code>false</code>
           and <var>previous definition</var> exists and is protected;
@@ -6923,6 +6929,10 @@ <h2>Changes since Candidate Release of 12 December 2019</h2>
       <a href="#expansion-algorithm">Expansion algorithm</a>
       to make sure the <a>type-scoped context</a> is not propagated by default.
       This is in response to <a href="https://github.com/w3c/json-ld-api/issues/243">Issue 246</a>.</li>
+    <li>Added missing keyworkds <a href="#ctd-invalid-entries">28</a> of the
+      <a href="#create-term-definition">Create Term Definition algorithm</a>
+      that remaining steps are skipped if the value of `@id` is `null`.
+      This is in response to <a href="https://github.com/w3c/json-ld-api/issues/261">Issue 261</a>.</li>
   </ul>
 </section>