bug#34749: 26.1; `delete-windows-on': (1) doc, (2) bug, (3) bug, (4) candidates

[Eli Zaretskii]

> Date: Mon, 4 Mar 2019 08:25:54 -0800 (PST)
> From: Drew Adams <drew.adams@oracle.com>
> 
> 1. The doc string should first of all completely describe the
> interactive behavior and only secondarily describe the Lisp behavior
> (completely).
> 
> In particular, this doc string should say explicitly what happens with a
> prefix arg, including what happens with different kinds of raw prefix
> arg (including, but not limited to, 0).

I fixed this, although not regarding the order.  the doc string is not
too long, so interspersing the description of interactive behavior
with non-interactive is not a catastrophe.

Btw, it is a pity that only the prefix arg of zero is useful in
interactive usage, which doesn't let the user select the other
behaviors regarding the optional FRAME argument.  I think this
could/should be improved by relatively straightforward changes that
use values of prefix arg other than zero.

> The doc string should also say that a prefix arg is ignored when the
> condition of the last paragraph applies (dedicated window alone in
> frame, with other frames existing), if that's true.

I didn't understand what this alludes to.