[partials/footer] Fix dangling <em>

themes/doublefourteen/layouts/partials/footer.html

@@ -7,6 +7,6 @@
       Code samples are MIT licensed, logos belong to their respective owners, everything else is
       <a href="https://creativecommons.org/licenses/by-sa/4.0/" class="external-link">
         CC BY-SA</a>.
-    <em>
+    </em>
   </small>
 </footer>