bug#20545: New minor mode Electric Punct

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sun, 10 May 2015 16:55:42 -0700
> From: Paul Eggert <eggert@cs.ucla.edu>
> 
> Attached are two proposed patches. The first creates a new minor mode Electric Punct that does a variant of "smart quoting" designed for the Emacs tradition of using ` and ' as aliases for left and right single quotation marks. This new minor mode is inactive by default

The documentation patch says it's enabled by default.

> but the user can enable it in certain contexts. The second patch modifies .dir-locals.el to enable the minor mode in contexts where it should be useful when editing Emacs itself.

I don't think we should enable this by default, not even in
.dir-locals.el.  Let users decide whether they want this; as for
Emacs, we didn't yet decide this style to be mandatory, so it's too
early to force it.

> These patches are related to Bug#20385 in that they make it much easier to edit doc strings formatted ‘like this’, which is the point of Bug#20385.

Do we already have a way of displaying ‘..’ on terminals that cannot
display them (notably, some TTYs)?  If not, we should add that before
we install these changes, and those in bug #20385.  I don't think we
can let doc strings have glyphless characters.