Fix an error (typo) of the following revision:

| ------------------------------------------------------------------------
  | r55430 | nicokruithof | 2010-04-12 22:32:11 +0200 (Mon, 12 Apr 2010) | 3 lines
  | 
  | Changed CGAL::Type<K> to K::Type to get derived kernels compiling.
  | Exception: Didn't change Circular_arc_point_2 as it is not defined by the default kernel.
  | 
  | ------------------------------------------------------------------------

GraphicsView/include/CGAL/Qt/Converter.h

@@ -146,7 +146,7 @@ public:
     return QLineF();
   }
 
-  QPolygonF operator()(const CGAL_Ray_2                 &t)
+  QPolygonF operator()(const CGAL_Triangle_2 &t)
   {
     QPolygonF qp;
     qp << operator()(t.vertex(0)) << operator()(t.vertex(1)) << operator()(t.vertex(2));