Improve definition of @nest.

Fixes #227.

Author: gkellogg

index.html

@@ -585,8 +585,7 @@ <h2>Syntax Tokens and Keywords</h2>
         <a>IRI</a>. This keyword is described in <a class="sectionRef" href="#default-vocabulary"></a>.</dd>
       <dt><code>@graph</code></dt><dd>Used to express a <a>graph</a>.
         This keyword is described in <a class="sectionRef" href="#named-graphs"></a>.</dd>
-      <dt class="changed"><code>@nest</code></dt><dd class="changed">Collects a set of <a>nested properties</a> within
-        a <a>node object</a>.</dd>
+      <dt class="changed"><code>@nest</code></dt><dd class="changed">Used to define a <a>property</a> of a <a>node object</a> that groups together properties of that node, but is not an edge in the graph.</dd>
       <dt class="changed"><code>@none</code></dt><dd class="changed">Used as an index value
         in an <a>index map</a>, <a>id map</a>, <a>language map</a>, <a>type map</a>, or elsewhere where a <a>map</a> is
         used to index into other values.</dd>