bug#20926: 25.0.50; Quotation marks always display as hard quotes

[Eli Zaretskii <eliz@gnu.org>]

> Date: Mon, 29 Jun 2015 16:22:49 +0100
> From: Artur Malabarba <bruce.connor.am@gmail.com>
> Cc: 20926@debbugs.gnu.org
> 
> 2015-06-29 16:10 GMT+01:00 Artur Malabarba <bruce.connor.am@gmail.com>:
> >> Go to that left quotation mark on the decomposition line, and type
> >> "C-u C-x =".  That should give you a hint about what's going on there.
> 
> Here's the output of doing that.

I knew how it will look, I wanted _you_ to see it. ;-)

This is the crucial part:

> Composed by the rule:
> #         v Round
> (TAB ?” TAB)

That's why this displays differently: it uses a composition rule,
which makes the display engine take a different path through the code.

This means that there's a hole in our machinery that takes care of
terminals incapable of displaying these characters: that machinery
doesn't catch auto-composed characters.

This doesn't explain why you see the original problem, but it should
explain why "C-u C-x =" shows the Unicode characters nonetheless.