Correction of (X)HTML warnings in case of Advanced topics

Based on suggestion of @sloriot using `^^` also in cgalAdvancedEnd instead of adding a new line in the files

Documentation/doc/resources/1.8.14/BaseDoxyfile.in

@@ -264,7 +264,7 @@ ALIASES                = "sc{1}=<span style=\"font-variant: small-caps;\">\1</sp
                          "cgalDebugEnd=\htmlonly[block] </div> \endhtmlonly" \
                          "cgalDebugFunction=This is a function for debugging purpose." \
                          "cgalAdvancedBegin=^^ \htmlonly[block] <div class=\"CGALAdvanced\"> <div>Advanced</div> \endhtmlonly ^^" \
-                         "cgalAdvancedEnd=\htmlonly[block] </div> \endhtmlonly" \
+                         "cgalAdvancedEnd=^^ \htmlonly[block] </div> \endhtmlonly" \
                          "cgalAdvancedFunction=This is an advanced function." \
                          "cgalAdvancedClass=This is an advanced class." \
                          "cgalAdvancedType=This is an advanced type." \

Periodic_2_triangulation_2/doc/Periodic_2_triangulation_2/CGAL/Periodic_2_triangulation_2.h

@@ -515,7 +515,6 @@ public:
   Converts the current triangulation into the same periodic
   triangulation in the 1-sheeted covering space.
   \pre `is_triangulation_in_1_sheet()`
-
   \cgalAdvancedEnd
   */
   void convert_to_1_sheeted_covering();
@@ -992,7 +991,6 @@ public:
   `f`. Face `f` is modified,
   two new faces are created. If the triangulation contains periodic copies, a point is inserted in all periodic copies.
   \pre The point in vertex `v` lies inside face `f`.
-
   \cgalAdvancedEnd
   */
   Vertex_handle insert_in_face(const Point& p, Face_handle f);
@@ -1002,7 +1000,6 @@ public:
   \cgalAdvancedBegin
   Removes a vertex of degree three. Two of the incident faces are
   destroyed, the third one is modified. \pre Vertex `v` is a vertex with degree three.
-
   \cgalAdvancedEnd
   */
   void remove_degree_3(Vertex_handle v);
@@ -1026,7 +1023,6 @@ public:
   `[edge_begin, edge_end]`. Returns a handle to the new vertex.
 
   \pre The triangulation is a triangulation of 1 sheet
-
     \cgalAdvancedEnd
   */
   template<class EdgeIt>
@@ -1042,7 +1038,6 @@ public:
   and create new ones only when the sequence is exhausted.
 
   \pre The triangulation is a triangulation of 1 sheet
-
   \cgalAdvancedEnd
   */
   template<class EdgeIt, class FaceIt>

Point_set_3/include/CGAL/Point_set_3.h

@@ -1164,7 +1164,6 @@ public:
     \return Returns a pair containing: the specified property map and a
     Boolean set to `true` or an empty property map and a Boolean set
     to `false` (if the property was not found).
-
     \cgalAdvancedEnd
   */
   template <class T>
@@ -1190,7 +1189,6 @@ public:
 
     \note The normal property must have been added to the point set
     before calling this method (see `add_normal_map()`).
-
     \cgalAdvancedEnd
   */
   Vector_push_map normal_push_map ()

TDS_3/doc/TDS_3/Concepts/TriangulationDataStructure_3.h

@@ -125,7 +125,6 @@ data structure that only changes the vertex type. It has to define a type
 `Rebind_vertex<Vb2>::%Other` which is a <I>rebound</I> triangulation data structure, that is, the 
 one whose `TriangulationDSVertexBase_3` will be `Vb2`.
 \note It can be implemented using a nested template class.
-
 \cgalAdvancedEnd
 */ 
 template <typename Vb2> 
@@ -139,7 +138,6 @@ data structure that only changes the cell type. It has to define a type
 `Rebind_cell<Cb2>::%Other` which is a <I>rebound</I> triangulation data structure, that is, the 
 one whose `TriangulationDSCellBase_3` will be `Cb2`.
 \note It can be implemented using a nested template class.
-
 \cgalAdvancedEnd
 */ 
 template <typename Cb2> 

Triangulation/doc/Triangulation/CGAL/Triangulation_data_structure.h

@@ -81,7 +81,6 @@ data structure that only changes the vertex type. It has to define a type
 `Other` which is a <I>rebound</I> triangulation data structure with `Vb2`
 as vertex type.
 \note It can be implemented using a nested template class.
-
 \cgalAdvancedEnd
 */
 template <typename Vb2> 
@@ -95,7 +94,6 @@ data structure that only changes the full cell type. It has to define a type
 `Other` which is a <I>rebound</I> triangulation data structure with `Fcb2`
 as full cell type.
 \note It can be implemented using a nested template class.
-
 \cgalAdvancedEnd
 */
 template <typename Fcb2> 
@@ -116,7 +114,6 @@ The boundary is recognized by checking the mark of the full cells.
 This method is used by `Triangulation_data_structure::insert_in_hole()`. 
 s
 \pre same as `TriangulationDataStructure::insert_in_hole()` 
-
 \cgalAdvancedEnd
 
 */ 

Triangulation/doc/Triangulation/Concepts/TriangulationDataStructure.h

@@ -450,7 +450,6 @@ All vertices of cells of \f$ C\f$ are on \f$ \partial H\f$.
 \cgalFigureBegin{triangulationfiginserthole,insert-in-hole.png}
 Insertion in a hole, \f$ d=2\f$
 \cgalFigureEnd
-
 \cgalAdvancedEnd
 */
 template< class ForwardIterator > Vertex_handle

Triangulation_2/doc/Triangulation_2/CGAL/Constrained_triangulation_plus_2.h

@@ -450,7 +450,6 @@ constraints based on a cost and stop function.
 \pre The vertex referred by vicq is not contained in any other constraint.
 \pre Let `vip` and `vir` be defined as `vip = std::prev(vicq)` and `vir = std::next(vicr)`.
 \pre The line segment between `*vicp->point()` and `*vicr->point()` must not intersect any constraint.
-
 \cgalAdvancedEnd
  */
 void