ISSUE:    Situation:
       1. Authors/generators sometimes do
          <style type="text/css"><!--/*HTML comment start*/
          body{background:yellow}
          -/*HTML comment end*/--></style>
       2. This is useless but harmless in text/html since
          the HTML parser does not treat them as comments
          when they occur inside <style> or <script>
       3. But in XML, the comments *do* have effect, 
          and the above example would thus not be 
          styled and could, in fact, even be deleted
          by XML parsers

SOLUTION:

          EITHER: only warn when the first non-white-space
                  character is a comment and that comment
                  spans the entire element.
   OR EVENTUALLY: take a more drastic step and always
                  warn whenever comments occurs inside
                  <style> or <script>.