bug#38443: 26.3; nitpicking: in server-process-filter's docstring, -position LINE[:COLUMN] should be -position +LINE[:COLUMN]

[Eli Zaretskii]

> From: Xu Chunyang <xuchunyang56@gmail.com>
> Date: Sun, 1 Dec 2019 22:01:57 +0800
> 
> C-h f server-process-filter says
> 
> `-position LINE[:COLUMN]'
>   Go to the given line and column number
>   in the next file opened.
> 
> but I find it doesn't work:
> 
> ~ $ nc -U $TMPDIR/emacs501/server
> -position 10 -file .
> -emacs-pid 284
> -error Invalid&_&-position&_command&_in&_client&_args
> -emacs-pid 284
> 
> however, -position +LINE[:COLUMN] works, in other words, + is missed
> in the docstring.

Thanks, fixed.