Merge #18054: net: reference instead of copy in BlockConnected range loop

9a299a5 net: reference instead of copy in BlockConnected range loop (Jon Atack)

Pull request description:

  Reference elements in range for loop instead of copying them and
  fix Clang `-Wrange-loop-analysis` warning introduced in a029e18

  ```
  net_processing.cpp:1185:25: warning: loop variable 'ptx' of
  type 'const std::shared_ptr<const CTransaction>' creates a copy from
  type 'const std::shared_ptr<const CTransaction>' [-Wrange-loop-analysis]
          for (const auto ptx : pblock->vtx) {
                          ^
  net_processing.cpp:1185:14: note: use reference type
  'const std::shared_ptr<const CTransaction> &' to prevent copying
          for (const auto ptx : pblock->vtx) {
               ^~~~~~~~~~~~~~~~
  1 warning generated.
  ```

ACKs for top commit:
  Empact:
    ACK bitcoin/bitcoin@9a299a5
  MarcoFalke:
    ACK 9a299a5
  promag:
    ACK 9a299a5.
  elichai:
    ACK 9a299a5
  emilengler:
    ACK 9a299a5.

Tree-SHA512: 9284d1b00684877505454a05071212758c8cea083534e2eec09bfc8a9c3059eea811d2008f6a5a678539444f0d5b3134db1bd23da6514b3d3a1440634c8b53be

Author: fanquake

src/net_processing.cpp

@@ -1182,7 +1182,7 @@ void PeerLogicValidation::BlockConnected(const std::shared_ptr<const CBlock>& pb
     }
     {
         LOCK(g_cs_recent_confirmed_transactions);
-        for (const auto ptx : pblock->vtx) {
+        for (const auto& ptx : pblock->vtx) {
             g_recent_confirmed_transactions->insert(ptx->GetHash());
         }
     }