Fix invalid HTML in the intro page

Author: eXpl0it3r

Source/Demo/Common/Samples/00.Intro.htm

@@ -10,7 +10,7 @@ <h1 align="center" style="color: white">
             <span style="font-size: x-small;">Release $$Release$$</span>
         </h1>
         <blockquote class="whitehole">
-            <p style="margin-top: 0px">
+            <div style="margin-top: 0px">
                 <table border="0" width="100%">
                     <tr style="vertical-align: top;">
                         <td width="32" style="padding: 2px 5px 0 0">
@@ -26,7 +26,7 @@ <h1 align="center" style="color: white">
                         </td>
                     </tr>
                 </table>
-            </p>
+            </div>
             <h3>
                 Text selection (copy to clipboard)
             </h3>