add example to the user manual

Tetrahedral_remeshing/doc/Tetrahedral_remeshing/Tetrahedral_remeshing.txt

@@ -107,5 +107,16 @@ from a polyhedral domain with features.
 
 \cgalExample{Tetrahedral_remeshing/mesh_and_remesh_polyhedral_domain_with_features.cpp}
 
+
+\subsection ssecEx5 Tetrahedral Remeshing from Any Tetrahedral Mesh
+
+The following example shows how to read a mesh from a triangulation stored in a
+Medit file, perform tetrahedral remeshing, and save the output triangulation.
+The input triangulation should follow the validity requirements of a
+`CGAL::Triangulation_3` (valid connectivity, positive orientation of the cells, and
+coverage of the convex hull of the vertices).
+
+\cgalExample{Tetrahedral_remeshing/tetrahedral_remeshing_from_mesh.cpp}
+
 */
 } /* namespace CGAL */