typo in html.tpl.php

Lines 90, 91, & 92 of html.tpl.php are missing trailing comment. Should read:

  <!--[if lt IE 7 ]-->
    <!--<script src="<?php echo $prtnrs_path;?>/js/libs/dd_belatedpng.js"></script>-->
    <!--<script> DD_belatedPNG.fix('img, .png_bg'); //fix any <img> or .png_bg background-images </script>-->

Minor, especially as easily caught by newbs like me on following ReadMe.txt install instructions, but thought worth correcting. Might otherwise cause validation problems if users aren’t getting into ie6 PNG support.