Add additional abbr and dfn tests to the demo

Author: necolas

demo.html

@@ -55,12 +55,12 @@ <h1>Text-level semantics</h1>
 
         <p>
         The <a href="#">a element</a> example<br>
-        The <abbr title="Title text">abbr element</abbr> example<br>
+        The <abbr>abbr element</abbr> and <abbr title="Title text">abbr element with title</abbr> examples<br>
         The <b>b element</b> example<br>
         The <cite>cite element</cite> example<br>
         The <code>code element</code> example<br>
         The <del>del element</del> example<br>
-        The <dfn>dfn element</dfn> example<br>
+        The <dfn>dfn element</dfn> and <dfn title="Title text">dfn element with title</dfn> examples<br>
         The <em>em element</em> example<br>
         The <i>i element</i> example<br>
         The img element <img src="http://placekitten.com/16/16" alt=""> example<br>