it's actually only the start. each time one wishes to bind a prefix to a
region of a namespace, well, one is going to have to include a namespace pi.
yes, that's once per document. don't look at me. don't even look at the wd's
authors. it's inherent in the encoding problem.
and yes, since a namespace pi does not permit docmentation, an element makes
sense to perform that task. that's one extra.