merge method

Creates a copy of this heuristics with rules from other appended.

Implementation

ParchmentHeuristics merge(ParchmentHeuristics other) {
  return ParchmentHeuristics(
    formatRules: formatRules..addAll(other.formatRules),
    insertRules: insertRules..addAll(other.insertRules),
    deleteRules: deleteRules..addAll(other.deleteRules),
  );
}