chore(core): cleanup code p3 (#16073)

* Update MMapMgr.cpp

* Update UpdateFetcher.cpp

* Update AuctionHouseMgr.cpp

* Update AuctionHouseMgr.h

* Update BattlegroundAV.cpp

* Update ChannelMgr.cpp

* Update ThreatMgr.h

* Update Player.h

* Update PlayerSettings.cpp

* Update ObjectMgr.cpp

* Update Guild.cpp

* Update Guild.h

* Update Map.cpp

* Update World.cpp

* Update boss_nefarian.cpp

* Update boss_prince_malchezaar.cpp

* Update boss_venoxis.cpp

* Update zone_elwynn_forest.cpp

* Update zulfarrak.cpp

* Update boss_novos.cpp

src/server/game/Chat/Channels/ChannelMgr.cpp

@@ -106,7 +106,7 @@ void ChannelMgr::LoadChannels()
         ++count;
     } while (result->NextRow());
 
-    for (auto pair : toDelete)
+    for (auto& pair : toDelete)
     {
         CharacterDatabasePreparedStatement* stmt = CharacterDatabase.GetPreparedStatement(CHAR_DEL_CHANNEL);
         stmt->SetData(0, pair.first);