docs: def config_pp(subs):
      """Pretty print of configuration options.
  
      Args:
          subs (iterable of str): iterable with the list of conf sections to
              print.
      """
      print('(c|f): available only as CLI argument/in the config file',
            end='\n\n')
      for sub in subs:
          hlp_lst = []
          for opt, meta in conf[sub].defaults_():
              if meta.cmd_arg ^ meta.conf_arg:
                  opt += ' (c)' if meta.cmd_arg else ' (f)'
              hlp_lst.append((opt, meta.help))
          if hlp_lst:
              print('{}:'.format(sub))
              _pretty_print(hlp_lst, sep=' -- ',
                            text_width=min(get_terminal_size().columns, 100))
              print()