DOCBOOK: revised - revhistory

revhistory in bookinfo does not display in HTML output;  

OK, I see why this is wrong; I got caught trying to infer a meaning without 
having read about it in TDG - even tried wrapping 
in printhistory and para;  still not printing

revhistory in para elsewhere in book *does* display in HTML output

why the difference?

TIA,
-- 
mueller, mike