bug#26925: Improve /doc/lispref/strings.texi (split-string) documentation

[Jean-Christophe Helary]

> On 2017/06/03, at 23:46, Eli Zaretskii <eliz@gnu.org> wrote:
> 
>> From: Jean-Christophe Helary <jean.christophe.helary@gmail.com>
>> Date: Sat, 3 Jun 2017 22:50:55 +0900
>> Cc: stephen.berman@gmx.net,
>> 26925@debbugs.gnu.org
>> 
>>>> -If the optional argument @var{trim}
>>>> →
>>>> +If @var{trim}
>>>> 
>>>> just to adapt the text to the description of the other arguments.
>>> 
>>> Thanks, but I see no problem with the current text.  We use both
>>> styles intermittently.
>> 
>> It's up to you. I thought it was weird that all the other optional arguments 
>> were not labeled as "optional" and only this one.
> 
> That's not what I see: grepping the ELisp manual for "optional
> argument" comes up with more than 200 hits.  It's quite normal to use
> that.

I am talking about this function. This function does not use "optional 
arguments" for its other optional arguments.

Jean-Christophe