bug#30502: 26.0.91; electric-pair-mode documentation

[Eli Zaretskii]

> Date: Sat, 17 Feb 2018 17:51:45 +0100
> From: charles@aurox.ch (Charles A. Roelli)
> CC: 30502@debbugs.gnu.org
> 
> The node does not mention anything about automatically
> inserting a matching delimeter at the mark when the region is active
> and a delimeter character is typed.

Thanks, I documented that now.  In the doc string of the mode as well.

> By "this functionality" I mean auto-inserting a matching delimeter at
> the mark when a delimeter character is typed, when electric-pair-mode
> is on.  The region has to be active for this to work, therefore
> transient-mark-mode must be on (even if temporarily).  I suggest
> adding a command that wraps point and mark with some given delimeters,
> regardless of whether the region is active.

We have "C-u C-x C-x" that turns on transient-mark-mode temporarily.
Isn't that enough?  If not, the issue is general, not specific to this
mode.