Update techniques/html/H4.html

Author: patrickhlauke

techniques/html/H4.html

@@ -18,7 +18,7 @@
       <p>When the interactive elements are navigated using the tab key, the elements are given
             focus in increasing order of the value of their <code>tabindex</code> attribute.
             Elements that have a <code>tabindex</code> value higher than <code>0</code> will receive focus
-            before elements without a <code>tabindex</code> or a <code>tabindex</code> of 0. After
+            before elements without a <code>tabindex</code> or a <code>tabindex</code> of <code>0</code>. After
             all of the elements with a tabindex higher than 0 have received focus, the rest of the
             interactive elements are given focus in the order in which they appear in the web
           page.</p>