+ DocBookTag footnote
+ DocBookItemTag para
+ DocBookWrapperTag title
+ DocBookWrapperTagType paragraph
+ DocBookWrapperMergeWithPrevious true
+ DocBookInInfo maybe
+ # TODO: the argument will be output within the tag, while it should be the xml:id attribute, i.e. the output should be <footnote xml:id="[Argument 1]"/>. And it should also be within the title, and not as a second title.