bug#19556: eww: make URI rewriting fully customizable

[Eli Zaretskii]

> From: Ivan Shmakov <ivan@siamics.net>
> Date: Sun, 11 Jan 2015 20:17:49 +0000
> 
> >>>>> Eli Zaretskii <eliz@gnu.org> writes:
> >>>>> From: Ivan Shmakov  Date: Sun, 11 Jan 2015 18:22:22 +0000
> 
>  >> What about президент.рф?
> 
>  >> … Well, right, – Emacs by itself doesn’t seem to offer IDN support
>  >> right now, but I guess that will change.  Eventually.
> 
>  > There's already idna.el, and Emacs uses it when it's available.
> 
>       Indeed, I’ve seen references to idna.el under lisp/gnus/, but
>       neither any references to it outside of that directory, nor
>       idna.el itself in the Emacs tree.

idna.el comes with libidn.  And one of the references you see is in
message.el, which is the default MUA in Emacs.  So not just Gnus uses
it.

>       In relation to my comment above, I see no mention of IDN under
>       lisp/url/ or in lisp/net/eww.el.

Volunteers are welcome to fill that gap.  The infrastructure is there
already, it just needs to be used.