bug#27494: 24.5; doc of `add-to-history'

bug#27494: 24.5; doc of `add-to-history'

[Drew Adams]

Both doc string and Elisp manual:

The doc should say that when MAXELT is exceeded the oldest history
element is discarded.  Yes, one might surmise that from the meaning of
"history" ,and from assuming that the new element is always added,
even if the history is full (up to MAXELT).  Still, it is better to be
explicit.

In GNU Emacs 24.5.1 (i686-pc-mingw32)
 of 2015-04-11 on LEG570
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --prefix=/c/usr --host=i686-pc-mingw32'

bug#27494: 24.5; doc of `add-to-history'

[Eli Zaretskii]

> Date: Sun, 25 Jun 2017 17:08:18 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> 
> Both doc string and Elisp manual:
> 
> The doc should say that when MAXELT is exceeded the oldest history
> element is discarded.  Yes, one might surmise that from the meaning of
> "history" ,and from assuming that the new element is always added,
> even if the history is full (up to MAXELT).  Still, it is better to be
> explicit.

The ELisp manual already said that the values of maximum length have
the same meaning as those of 'history-length', so I just added the
same reference to the doc string.

Thanks.