public List<String> unmatchedClasses() {
			if (parent == null) return Collections.emptyList();
			return Lists.combine(parent.unmatchedClasses(), parent.rule.classes());
		}
@return List of classes for unmatched sections in this region.
recaf-ui/src/main/java/software/coley/recaf/ui/control/richtext/syntax/RegexSyntaxHighlighter.java