Fix switch warnings (#4013)

* Fix switch warnings
  * Fix a variety of -Wswitch and -Wswitch-enum warnings
  * Remove unneeded -Wno-error flags

* Reorganise some eMonsterType switches
  * Alpha sort eMonsterType cases in WriteMobMetadata
    and in cNBTChunkSerializer::AddMonsterEntity
  * List all mob types in protocol 1.12 and NBTChunkSerializer

* cStructGenTrees::GetNumTrees: remove switch default

* cWSSAnvil::LoadOldMinecartFromNBT: Log unhandled minecart type

src/Items/ItemHandler.cpp

@@ -659,9 +659,9 @@ char cItemHandler::GetMaxStackSize(void)
 		case E_ITEM_SUGAR_CANE:           return 64;
 		case E_ITEM_TIPPED_ARROW:         return 64;
 		case E_ITEM_WHEAT:                return 64;
+		// By default items don't stack:
+		default:                          return 1;
 	}
-	// By default items don't stack:
-	return 1;
 }