Remove trailing comma in discussion of language map values.

Author: gkellogg

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

@@ -1484,7 +1484,7 @@ <h3>Algorithm</h3>
                       <em>language value</em>.</li>
                     <li>For each <em>item</em> in <em>language value</em>:
                       <ol class="algorithm">
-                        <li><em>item</em> must be a <a>string</a>,
+                        <li><em>item</em> must be a <a>string</a>
                           <span class="changed">or <code>null</code></span>,
                           otherwise an
                           <a data-link-for="JsonLdErrorCode">invalid language map value</a>