message: refactor: use const reference for parents in `CTxMemPool::UpdateAncestorsOf`
diff: @@ -278,7 +278,7 @@ bool CTxMemPool::CalculateMemPoolAncestors(const CTxMemPoolEntry &entry,
  void CTxMemPool::UpdateAncestorsOf(bool add, txiter it, setEntries &setAncestors)
  {
  - CTxMemPoolEntry::Parents parents = it->GetMemPoolParents();
  + const CTxMemPoolEntry::Parents& parents = it->GetMemPoolParentsConst();
  // add or remove this tx as a child of each parent
  for (const CTxMemPoolEntry& parent : parents) {
  UpdateChild(mapTx.iterator_to(parent), it, add);
  