((contrast)) is a hatnote for categories.
((contrast |antonym category (|second antonym category)))
i.e. the category contrasted is taken to be ((PAGENAME)) (the name of the page on which ((contrast)) is transcluded).
((contrast|X|Y)) produces: To change the copula from "is" to "are", include|copula=are
or |plural=true
(or "on
", "yes
", etc).