bug#23377: 25.0.93; Completion is extremely slow for insert-char

[Stefan Monnier]

> I hope Stefan will be able to answer that, as he introduced the
> feature a year ago.

Just so you can see what the char looks like.  It's not always obvious
from its name.  I think it's a pretty obviously desirable feature.

But in my case at least it wouldn't be worth waiting a minute to see those
chars, so I'm perfectly OK with disabling it by default (on my machines
it doesn't take very long to show up, so I'll enable it in my ~/.emacs).

> There was a long discussion at some point of how to facilitate
> selection of characters to insert, if you don't know their exact name
> or codepoint, so I presume this feature was supposed to help in that
> area.

The feature predates this discussion, but indeed it goes in the same
direction (tho I think the discussion was aimed more at choosing based
on broad categories first, then the char's appearance, so the
*Completions* list of `C-x 8 RET` is pretty far from that, showing only
a single char per line, with no grouping into categories).


        Stefan