Update terms.

Author: gkellogg

common/terms.html

@@ -331,7 +331,7 @@
     or an <a>expanded term definition</a>.
   </dd>
   <dt class="changed"><dfn data-cite="JSON-LD11#dfn-type-map">type map</dfn></dt><dd class="changed">
-    An <a>type map</a> is a <a>map</a> value of a <a>term</a>
+    A <a>type map</a> is a <a>map</a> value of a <a>term</a>
     defined with <code>@container</code> set to <code>@type</code>,
     whose keys are interpreted as <a>IRIs</a>
     representing the <code>@type</code> of the associated <a>node object</a>;