Review check in simplify_terms()

[hfrick]

Is this check necessary? We only call simplify_terms() on objects that have passed through model.frame() via model_frame().

hardhat/R/util.R

Lines 16 to 18 in 92ad391

	if (!is_terms) {
	abort("`x` must be a terms object")
	}

[topepo]

Sure. It's only used in a closed system where we create the terms from scratch, so there is a low risk of ever occurring (and probably isn't testable).