Add setting for whether non-leading train engines keep custom names

src/settings_gui.cpp

@@ -2267,6 +2267,7 @@ static SettingsContainer &GetSettingsTree()
 			vehicles->Add(new SettingEntry("order.nonstop_only"));
 			vehicles->Add(new SettingEntry("vehicle.adjacent_crossings"));
 			vehicles->Add(new SettingEntry("vehicle.safer_crossings"));
+			vehicles->Add(new SettingEntry("vehicle.non_leading_engines_keep_name"));
 		}
 
 		SettingsPage *limitations = main->Add(new SettingsPage(STR_CONFIG_SETTING_LIMITATIONS));