Add unset hotkey for industry chains window

src/toolbar_gui.cpp

@@ -2006,6 +2006,7 @@ enum MainToolbarHotkeys {
 	MTHK_GRAPHS,
 	MTHK_LEAGUE,
 	MTHK_INDUSTRIES,
+	MTHK_INDUSTRY_CHAINS,
 	MTHK_TRAIN_LIST,
 	MTHK_ROADVEH_LIST,
 	MTHK_SHIP_LIST,
@@ -2112,6 +2113,7 @@ struct MainToolbarWindow : Window {
 			case MTHK_GRAPHS: ShowOperatingProfitGraph(); break;
 			case MTHK_LEAGUE: ShowCompanyLeagueTable(); break;
 			case MTHK_INDUSTRIES: ShowBuildIndustryWindow(); break;
+			case MTHK_INDUSTRY_CHAINS: ShowIndustryCargoesWindow(); break;
 			case MTHK_TRAIN_LIST: ShowVehicleListWindow(_local_company, VEH_TRAIN); break;
 			case MTHK_ROADVEH_LIST: ShowVehicleListWindow(_local_company, VEH_ROAD); break;
 			case MTHK_SHIP_LIST: ShowVehicleListWindow(_local_company, VEH_SHIP); break;
@@ -2232,6 +2234,7 @@ static Hotkey maintoolbar_hotkeys[] = {
 	Hotkey(WKC_F10, "graphs", MTHK_GRAPHS),
 	Hotkey(WKC_F11, "league", MTHK_LEAGUE),
 	Hotkey(WKC_F12, "industry_list", MTHK_INDUSTRIES),
+	Hotkey((uint16)0, "industry_chains", MTHK_INDUSTRY_CHAINS),
 	Hotkey(WKC_SHIFT | WKC_F1, "train_list", MTHK_TRAIN_LIST),
 	Hotkey(WKC_SHIFT | WKC_F2, "roadveh_list", MTHK_ROADVEH_LIST),
 	Hotkey(WKC_SHIFT | WKC_F3, "ship_list", MTHK_SHIP_LIST),