Example from Edi Weitz' Lisp package HTML-Template
(http://weitz.de/html-template/):
<table border=1>
<!-- TMPL_LOOP rows -->
<tr>
<!-- TMPL_LOOP cols -->
<!-- TMPL_IF colorful-style -->
<td align="right" bgcolor="pink"><!-- TMPL_VAR content --></td>
<!-- TMPL_ELSE -->
<td align="right" ><!-- TMPL_VAR content --></td>
<!-- /TMPL_IF -->
<!-- /TMPL_LOOP -->
</tr>
<!-- /TMPL_LOOP -->
</table>
is indented in html-mode
<html>
<table border=1>
<!-- TMPL_LOOP rows -->
<tr>
<!-- TMPL_LOOP cols -->
<!-- TMPL_IF colorful-style -->
<td align="right" bgcolor="lime"><!-- TMPL_VAR content --></td>
<!-- TMPL_ELSE -->
<td align="right" ><!-- TMPL_VAR content --></td>
<!-- /TMPL_IF -->
<!-- /TMPL_LOOP -->
</tr>
<!-- /TMPL_LOOP -->
</table>
</html>
because the comment-like tags "<!-- TMPL ..." are unknown. How do I
teach html-mode to recognize their special meaning?