Process metadata annotation.

def process_annotation(self, ann):
        """Process metadata annotation."""
        tmpl = self.xsl_template("@" + self.qname(ann))
        ET.SubElement(tmpl, "param", name="level", select="0")
        ct = self.xsl_calltemplate("leaf", tmpl)
        ET.SubElement(ct, "with-param", name="level", select="$level")
        self.xsl_withparam("nsid", ann.i_module.i_modulename + ":", ct)
        self.type_param(ann, ct)