src/vs/platform/theme/common/tokenClassificationRegistry.ts/equals
	export function equals(r1: SemanticTokenRule | undefined, r2: SemanticTokenRule | undefined) {
		if (r1 === r2) {
			return true;
		}
		return r1 !== undefined && r2 !== undefined
			&& r1.selector && r2.selector && r1.selector.id === r2.selector.id
			&& TokenStyle.equals(r1.style, r2.style);
	}