Changes

{{cmd|dodoubleempty}} is used to write commands that can take zero, one, or two square-bracketed arguments: if the user specifies less than two arguments, it adds empty arguments at the end to make up the missing numbers.  {{cmd|dodoubleargument|link=no}} used to be a variant that required exactly two arguments, but is now a synonym. It is still used alongside {{cmd|dodoubleempty}} to remind the programmer that the arguments are requird instead of optional, but the difference is semantic rather than syntactic.