The line "The `cons' operator for creating list cells has changed from the pretty atom '.' to the ugly atom '[|]', so we can use the '.' for other purposes. See section 5.4.1." is utterly unhelpful. I can find no way to use the cons operator in question, and the linked 5.4.1 doesn't relate to this issue at all; it's merely explaining what ./2 is used for.
Perhaps a simple example of using '[|]' is in order? Because I can't even find '[|]' used in the SWI source code anywhere.