bug#52741: [External] : Re: bug#52741: 27.2; Doc string of `visual-line-mode'

[Drew Adams]

> > What on earth is ARG, for interactive use?  The description of
> > interactive use should talk about things like a prefix arg, not about
> > unexplained things like ARG.  How will a user know how to pass argument
> > ARG interactively?
> 
> It's standard -- every user should know how to give a command a numeric arg.

Sure.  But the doc string normally says, "With a
prefix arg...", or "A numeric prefix arg means...".
or some such.

It doesn't talk about an undescribed ARG in the
context of interactive use.  If it talks about ARG
in that context, it tells you it's the prefix arg.

This is the relevant part of the doc string in
question, for Emacs 27.2, which is what I reported on:

 If called interactively, enable Visual-Line mode if
 ARG is positive, and disable it if ARG is zero or
 negative.

What's missing there is "prefix" or (preferably)
"numeric prefix", before "ARG" (or "arg").