docs: def deprecated(f):
      """Decorate a function object as deprecated.
  
      Work nicely with the @command and @subshell decorators.
  
      Add a __deprecated__ field to the input object and set it to True.
      """
      def inner_func(*args, **kwargs):
          print(textwrap.dedent("""\
                  This command is deprecated and is subject to complete
                  removal at any later version without notice.
                  """))
          f(*args, **kwargs)
      inner_func.__deprecated__ = True
      inner_func.__doc__ = f.__doc__
      inner_func.__name__ = f.__name__
      if iscommand(f):
          inner_func.__command__ = f.__command__
      return inner_func