Fix grammar: @annotation is allowed in node objects

This addresses #196.

Author: lanthaler

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

@@ -2761,36 +2761,37 @@ <h3>Node Object</h3>
 
 <p>A <tdef>node object</tdef> represents zero or more properties of a
   <tref>node</tref> in the <tref>JSON-LD graph</tref> serialized by the
-  <tref>JSON-LD document</tref>.
+  <tref>JSON-LD document</tref>. A <tref>JSON object</tref> is a
+  <tref>node object</tref> if it exists outside of a JSON-LD
+  <tref>context</tref> and:</p>
 
-  A <tref>JSON Object</tref> is a <tref>node object</tref> if
-  it exists outside of the JSON-LD Context and:</p>
-
-  <ul>
-    <li>it does not contain the <code>@value</code>, <code>@list</code>,
-    <code>@annotation</code>, or <code>@set</code> keywords, or</li>
-    <li>it does not contain the <code>@graph</code> keyword and is
-    the top-most <tref>JSON Object</tref> in the JSON-LD document.
-  </ul>
+<ul>
+  <li>it does not contain the <code>@value</code>, <code>@list</code>,
+    or <code>@set</code> keywords, or</li>
+  <li>it does not contain the <code>@graph</code> keyword and is
+    the top-most <tref>JSON object</tref> in the JSON-LD document.
+</ul>
 
-  The properties of a <tref>node</tref> in the <tref>JSON-LD graph</tref>
-  may be spread among different <tref title="node object">node objects</tref>
-  within a document. When that happens,
-  the keys of the different <tref title="node object">node objects</tref>
-  are merged to create the properties of the resulting <tref>node</tref>.</p>
+<p>The <tref title="property">properties</tref> of a <tref>node</tref> in
+  the <tref>JSON-LD graph</tref> may be spread among different
+  <tref title="node object">node objects</tref> within a document. When
+  that happens, the keys of the different
+  <tref title="node object">node objects</tref> are merged to create the
+  properties of the resulting <tref>node</tref>.</p>
 
 <p>A <tref>node object</tref> MUST be a <tref>JSON object</tref> that contains
-  one or more key-value pairs. Keys MUST either be
-  <tref title="IRI">IRIs</tref>,
-  <tref title="compact IRI">compact IRIs</tref>,
-  <tref title="term">terms</tref> valid in the <tref>active context</tref>, or
-  one of the following <tref title="keyword">keywords</tref>:</p>
+  one or more key-value pairs. All keys which are not <tref title="IRI">IRIs</tref>,
+  <tref title="compact IRI">compact IRIs</tref>, <tref title="term">terms</tref>
+  valid in the <tref>active context</tref>, or one of the following
+  <tref title="keyword">keywords</tref> MUST be ignored when processed:</p>
+
 <ul>
   <li><code>@context</code>,</li>
   <li><code>@graph</code>,</li>
   <li><code>@id</code>, or</li>
   <li><code>@type</code></li>
 </ul>
+
 <p>If the <tref>node object</tref> contains the <code>@context</code>
   key, its value MUST be one of the following:</p>
 <ul>