[gtkmm] Gtk::ToolButton: Fix property_icon_widget()

[Kjell Ahlstedt <kjellahl src gnome org>]

commit 16bf57a560d1dcd68f5e1ec7a272066508ef79ce
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Mon Jan 28 16:44:41 2019 +0100

    Gtk::ToolButton: Fix property_icon_widget()
    
    Its type shall be Gtk::Widget*, not Gtk::Widget.

 gtk/src/toolbutton.hg | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtk/src/toolbutton.hg b/gtk/src/toolbutton.hg
index 402203f2..49ceccbd 100644
--- a/gtk/src/toolbutton.hg
+++ b/gtk/src/toolbutton.hg
@@ -78,7 +78,7 @@ public:
   _WRAP_PROPERTY("use_underline", bool)
   _WRAP_PROPERTY("label_widget", Gtk::Widget*)
   _WRAP_PROPERTY("icon_name", Glib::ustring)
-  _WRAP_PROPERTY("icon_widget", Gtk::Widget)
+  _WRAP_PROPERTY("icon_widget", Gtk::Widget*)
 };
 
 } // namespace Gtk