Fossil currently always delivers web page content as text/html to the browser.

Following the guidelines in <a the attached patch delivers the application/xhtml+xml content type instead when appropriate.

This will allow the use of the <nowiki>&lt;![CDATA[ ... anything not escaped ... ]]></nowiki> construct in future fossil output which should facilitate embedding arbitrary command output into the returned web pages (such as for rebuild and sync when used from the web ui).

NOTE: The patch attached to ticket [5ff2043c96] should also be applied or else invalid xhtml can be sent to the browser.