bug#3179: Entering Chinese "zero": add U+3007

[Eli Zaretskii]

> From: handa <handa@gnu.org>
> Cc: larsi@gnus.org, stepnem@gmail.com, 3179@debbugs.gnu.org,
>  jidanni@jidanni.org
> Date: Thu, 28 Nov 2019 22:18:25 +0900
> 
> I agree that "ling2" sould correspond to U+3007 rather than to the
> current U+25CB (WHITE CIRCLE).  For the latter, if we dare to assign
> some key sequence, it should be "wan2" (the key sequence for "丸" (the
> meaning is circle)).
> 
> I don't remember why quail-ext.el has such a code.  As it is in
> quail-ext.el, perhaps it was a request from some Chinese user.

Thanks, I added U+25CB to "wan2".