Add a comment to explain how Regular_triangulation_euclidean_traits works

+ remove misleading template parameter list in the doc

Triangulation/doc/Triangulation/CGAL/Regular_triangulation.h

@@ -42,7 +42,7 @@ tag `CGAL::Default` as the second parameter.
 */
 template< typename RegularTriangulationTraits_, typename TriangulationDataStructure_ >
 class Regular_triangulation
-  : public Triangulation<RegularTriangulationTraits_, TriangulationDataStructure_>
+  : public Triangulation
 {
 public:
 

Triangulation/include/CGAL/Regular_triangulation_euclidean_traits.h

@@ -26,6 +26,14 @@
 
 namespace CGAL {
 
+// Wrapper class to make a model of `RegularTriangulationTraits` easily usable
+// by the `Regular_triangulation` class. By using this class:
+// - Point_d (used by `Triangulation` and the TDS) becomes a weighted point
+// - Predicates and functors such as Less_coordinate_d or Orientation_d
+//   can be called using weighted points instead of bare points (this is
+//   needed because `Weighted_point_d` is not convertible to `Point_d`)
+// This way, `Triangulation` works perfectly well with weighted points.
+
 template <class K>
 class Regular_triangulation_euclidean_traits
   : public K