output html in docdetails

[rsteph-de]

Some metadata elements contain encoded html which should be rendered properly in the docdetails view.

The attribute disable-output-escaping=yes does not work, if the xml is generated within an xsl:param and procecced / copied within an other template.

The effect, known as "sticky doe" (doe=disable-output-escaping), worked in XSLT1 but not longer in XSLT3
(https://saxonica.plan.io/issues/3214)