Change asciidoc backend to more recent name.
The latest asciidoc doesn't have an 'html' backend. 'html' was last valid
with version 6 ( 2005-1-28). Current options are xhtml11, or
html4, with xhtml11 by default.
#header#
<title>Mercurial repositories index</title>
</head>
<body>
<h2>Mercurial Repositories</h2>
The specified repository "#repo#" is unknown, sorry.
Please go back to the main repository list page.
#footer#