Constant selectors::matching::HAS_SLOW_SELECTOR

pub const HAS_SLOW_SELECTOR: ElementSelectorFlags = ElementSelectorFlags{bits: 1 << 0,}

When a child is added or removed from the parent, all the children must be restyled, because they may match :nth-last-child, :last-of-type, :nth-last-of-type, or :only-of-type.