message: added documentation in the user manual
diff: @@ -640,6 +640,7 @@ Function name single double single compl
  :cpp:func:`rocsparse_coosort_buffer_size`
  :cpp:func:`rocsparse_coosort_by_row`
  :cpp:func:`rocsparse_coosort_by_column`
  +:cpp:func:`rocsparse_Xnnz` x x x x
  ===================================================== ====== ====== ============== ==============
  Storage schemes and indexing base
  @@ -1332,3 +1333,14 @@ rocsparse_coosort_by_column()
  -----------------------------
  .. doxygenfunction:: rocsparse_coosort_by_column
  +
  +rocsparse_nnz()
  +-------------------
  +
  +.. doxygenfunction:: rocsparse_snnz
  + :outline:
  +.. doxygenfunction:: rocsparse_dnnz
  + :outline:
  +.. doxygenfunction:: rocsparse_cnnz
  + :outline:
  +.. doxygenfunction:: rocsparse_znnz
  