message: add example to the list of examples
diff: @@ -22,6 +22,7 @@ Examples
  * :download:`rips_complex_diagram_persistence_from_off_file_example.py <../example/rips_complex_diagram_persistence_from_off_file_example.py>`
  * :download:`rips_complex_diagram_persistence_from_distance_matrix_file_example.py <../example/rips_complex_diagram_persistence_from_distance_matrix_file_example.py>`
  * :download:`rips_persistence_diagram.py <../example/rips_persistence_diagram.py>`
  + * :download:`sparse_rips_persistence_diagram.py <../example/sparse_rips_persistence_diagram.py>`
  * :download:`random_cubical_complex_persistence_example.py <../example/random_cubical_complex_persistence_example.py>`
  * :download:`coordinate_graph_induced_complex.py <../example/coordinate_graph_induced_complex.py>`
  * :download:`functional_graph_induced_complex.py <../example/functional_graph_induced_complex.py>`
  