SigSingleQuotes does not work as described in
http://c2.com/cgi/wiki?SixSingleQuotes . I don't know if this is a bug, or if
it is supposed to work differently. There is no description in detail of how
it is supposed to work in the help files, but just a link in HelpOnLinking to
that file, and it works differently on MoinMoin than on that wiki.