bug#33331: 26; doc strings of `tabify' and `untabify'

[Drew Adams <drew.adams@oracle.com>]

> > Please say why there is an unused optional arg ARG.
> 
> ??? The below is from the doc strings of both functions:
> 
>   If called interactively with prefix ARG, convert for the entire
>   buffer.
> 
> What am I missing?

Sorry, I missed that somehow.  Might have
been tripped up by the use of `_arg'; dunno.
I'll close the bug.

That said...

AFAICT there's no need to add that optional
arg.  This would have been sufficient, and
it is what I would have expected:

(defun untabify (start end)
  "..."
  (interactive
    (if current-prefix-arg
        (list (point-min) (point-max))
      (list (region-beginning) (region-end))))
  ...)

Am I missing something?  Does adding that arg,
and using it only in `interactive', help?

Seems like when someone added the prefix-arg
behavior (Emacs 24, apparently) they went
overboard a bit.  Not a problem; just a bit
weird, to my eyes.