bug#37213: Execute set-window-margins. left-margin-width remains 0.

[Eli Zaretskii]

> Date: Sat, 31 Aug 2019 11:59:11 +0000
> Cc: 37213@debbugs.gnu.org
> From: Alan Mackenzie <acm@muc.de>
> 
> How about the following, purely pragmatic, patch?
> 
> 
> diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi
> index 7c0a56dcad..428fe9595a 100644
> --- a/doc/lispref/display.texi
> +++ b/doc/lispref/display.texi
> @@ -5016,7 +5016,9 @@ Display Margins
>    Setting these variables does not immediately affect the window.  These
>  variables are checked when a new buffer is displayed in the window.
>  Thus, you can make changes take effect by calling
> -@code{set-window-buffer}.
> +@code{set-window-buffer}.  Do not use these variables to try to
> +determine the current width of the left or right margin.  Instead, use
> +the function @code{window-margins}.
>  
>    You can also set the margin widths immediately.

Fine with me, thanks.