Add Window::InitScrollWidgets()

This is just a wrapper around WindowInitScrollWidgets(), but better
matches the code style.

src/openrct2-ui/interface/Window.cpp

@@ -707,6 +707,11 @@ void Window::OnDrawWidget(rct_widgetindex widgetIndex, rct_drawpixelinfo& dpi)
     WidgetDraw(&dpi, this, widgetIndex);
 }
 
+void Window::InitScrollWidgets()
+{
+    WindowInitScrollWidgets(this);
+}
+
 void Window::InvalidateWidget(rct_widgetindex widgetIndex)
 {
     widget_invalidate(this, widgetIndex);