Fixed signature of the writeProlog method (should be const)

src/TNL/Meshes/Mesh.h

@@ -170,7 +170,7 @@ class Mesh
 
       bool operator!=( const Mesh& mesh ) const;
 
-      void writeProlog( Logger& logger );
+      void writeProlog( Logger& logger ) const;
 
    protected:
       // Methods for the mesh initializer

src/TNL/Meshes/MeshDetails/Mesh_impl.h

@@ -296,7 +296,7 @@ operator!=( const Mesh& mesh ) const
 template< typename MeshConfig, typename Device >
 void
 Mesh< MeshConfig, Device >::
-writeProlog( Logger& logger )
+writeProlog( Logger& logger ) const
 {
    logger.writeParameter( "Dimension:", getMeshDimension() );
    logger.writeParameter( "Number of cells:", getEntitiesCount< getMeshDimension() >() );