module header:
  Just " `elem`, 'print',
`Unknown',
'<>', ':=:', 'Bool'
"
declaration docs:
  elem:
    " '()', 'elem'."
  D:
    " A datatype."
  D0:
    " A constructor for 'D'. '"
  D1:
    " Another constructor"
  P:
    " A class"
  p:
    " A class method"
  $fShowD:
    " 'Show' instance"
  D':
    " Another datatype...

 ...with two docstrings."
arg docs:
  add:
    0:
      " First summand for 'add'"
    1:
      " Second summand"
    2:
      " Sum"
  p:
    0:
      " An argument"