Changed XHTML validator icon to HTML5 (FS#2619)

lib/tpl/dokuwiki/tpl_footer.php

@@ -20,8 +20,8 @@ if (!defined('DOKU_INC')) die();
             src="<?php echo tpl_basedir(); ?>images/button-donate.gif" width="80" height="15" alt="Donate" /></a>
         <a href="http://www.php.net" title="Powered by PHP" <?php echo $target?>><img
             src="<?php echo tpl_basedir(); ?>images/button-php.gif" width="80" height="15" alt="Powered by PHP" /></a>
-        <a href="http://validator.w3.org/check/referer" title="Valid XHTML 1.0" <?php echo $target?>><img
-            src="<?php echo tpl_basedir(); ?>images/button-xhtml.png" width="80" height="15" alt="Valid XHTML 1.0" /></a>
+        <a href="http://validator.w3.org/check/referer" title="Valid HTML5" <?php echo $target?>><img
+            src="<?php echo tpl_basedir(); ?>images/button-html5.png" width="80" height="15" alt="Valid HTML5" /></a>
         <a href="http://jigsaw.w3.org/css-validator/check/referer?profile=css3" title="Valid CSS" <?php echo $target?>><img
             src="<?php echo tpl_basedir(); ?>images/button-css.png" width="80" height="15" alt="Valid CSS" /></a>
         <a href="http://dokuwiki.org/" title="Driven by DokuWiki" <?php echo $target?>><img