Create WindowColour enum for widget definition calls (#12722)

* Make MakeWidget* functions take enum colour

* Make windows A-D use WindowColour enum

* Make windows E-G use WindowColour enum

* Make windows I-M use WindowColour enum

* Make windows N-P use WindowColour enum

* Make windows R-S use WindowColour enum

* Make windows T use WindowColour enum

* Make windows V-W use WindowColour enum

src/openrct2-ui/windows/EditorMain.cpp

@@ -49,7 +49,7 @@ static rct_window_event_list window_editor_main_events = {
 };
 
 static rct_widget window_editor_main_widgets[] = {
-    MakeWidget({ 0, 0 }, { 0, 0 }, WWT_VIEWPORT, 0, STR_VIEWPORT),
+    MakeWidget({ 0, 0 }, { 0, 0 }, WWT_VIEWPORT, WindowColour::Primary, STR_VIEWPORT),
     { WIDGETS_END },
 };