Feature: Button to toggle showing advanced signal types (#9617)

src/lang/english.txt

@@ -2674,6 +2674,7 @@ STR_STATION_CLASS_WAYP                                          :Waypoints
 
 # Signal window
 STR_BUILD_SIGNAL_CAPTION                                        :{WHITE}Signal Selection
+STR_BUILD_SIGNAL_TOGGLE_ADVANCED_SIGNAL_TOOLTIP                 :{BLACK}Toggle showing advanced signal types
 STR_BUILD_SIGNAL_SEMAPHORE_NORM_TOOLTIP                         :{BLACK}Block Signal (semaphore){}This is the most basic type of signal, allowing only one train to be in the same block at the same time
 STR_BUILD_SIGNAL_SEMAPHORE_ENTRY_TOOLTIP                        :{BLACK}Entry Signal (semaphore){}Green as long as there is one or more green exit-signal from the following section of track. Otherwise it shows red
 STR_BUILD_SIGNAL_SEMAPHORE_EXIT_TOOLTIP                         :{BLACK}Exit Signal (semaphore){}Behaves in the same way as a block signal but is necessary to trigger the correct colour on entry & combo pre-signals

src/rail_gui.cpp

@@ -1823,6 +1823,12 @@ public:
 				}
 				break;
 
+			case WID_BS_TOGGLE_SIZE:
+				_settings_client.gui.signal_gui_mode = (_settings_client.gui.signal_gui_mode == SIGNAL_GUI_ALL) ? SIGNAL_GUI_PATH : SIGNAL_GUI_ALL;
+				this->SetSignalUIMode();
+				this->ReInit();
+				break;
+
 			default: break;
 		}
 
@@ -1851,6 +1857,7 @@ static const NWidgetPart _nested_signal_builder_widgets[] = {
 	NWidget(NWID_HORIZONTAL),
 		NWidget(WWT_CLOSEBOX, COLOUR_DARK_GREEN),
 		NWidget(WWT_CAPTION, COLOUR_DARK_GREEN, WID_BS_CAPTION), SetDataTip(STR_BUILD_SIGNAL_CAPTION, STR_TOOLTIP_WINDOW_TITLE_DRAG_THIS),
+		NWidget(WWT_IMGBTN, COLOUR_DARK_GREEN, WID_BS_TOGGLE_SIZE), SetDataTip(SPR_LARGE_SMALL_WINDOW, STR_BUILD_SIGNAL_TOGGLE_ADVANCED_SIGNAL_TOOLTIP),
 	EndContainer(),
 	NWidget(NWID_VERTICAL, NC_EQUALSIZE),
 		NWidget(NWID_HORIZONTAL, NC_EQUALSIZE),

src/widgets/rail_widget.h

@@ -79,6 +79,7 @@ enum BuildRailStationWidgets {
 /** Widgets of the #BuildSignalWindow class. */
 enum BuildSignalWidgets {
 	WID_BS_CAPTION,            ///< Caption for the Signal Selection window.
+	WID_BS_TOGGLE_SIZE,        ///< Toggle showing advanced signal types.
 	WID_BS_SEMAPHORE_NORM,     ///< Build a semaphore normal block signal.
 	WID_BS_SEMAPHORE_ENTRY,    ///< Build a semaphore entry block signal.
 	WID_BS_SEMAPHORE_EXIT,     ///< Build a semaphore exit block signal.