Fix more source line numbers from #16622
Trac #16626: ellipsis for doctest line numbers

Warnings (including deprecations) should be of the form
{{{
   sage: raise_warning()
   doctest:...: Warning: this is a warning
}}}
Note the ellipsis. Putting the actual source line number in there is not
cool.

URL: http://trac.sagemath.org/16626
Reported by: vbraun
Ticket author(s): Volker Braun
Reviewer(s): Martin Albrecht, Dima Pasechnik