[gtkmm] Function parameter is not wrapped

["Andrew E. Makeev" <andrew solvo ru>]

treeviewcolumn.cc/h

void TreeViewColumn::set_widget(GtkWidget* widget)
{
  gtk_tree_view_column_set_widget(gobj(), widget);
}
---------------------------------------------------
patch

void TreeViewColumn::set_widget(Widget& widget)
{
  gtk_tree_view_column_set_widget(gobj(), widget.gobj());
}


Regards,
-andrew