bug#54027: Wishlist: Support full CSI u specification for terminal input

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: Eli Zaretskii <eliz@gnu.org>,  54027@debbugs.gnu.org
> Date: Sun, 27 Feb 2022 22:49:58 -0500
> 
> Alex Hutcheson [2022-02-27 13:21:20] wrote:
> >> I think just adding the missing combinations is a better way forward.
> > I think we're in agreement here, I was just suggesting how to add
> > the combinations to xterm.el without introducing a lot of boilerplate
> > code.
> 
> Actually, for `ESC [ 27 ...` the better option is to bind `ESC [ 27` to
> a function that reads the subsequent parameters so it will handle *all*
> cases in one go, as in the barely tested patch below.
> 
> For `ESC [ ... u` it's a bit more tricky because it doesn't have such
> a "clean" prefix (it's distinguished by the final `u` instead), so we'd
> have to rework a lot of the rest of the `ESC [` bindings.
> Maybe not a bad idea, tho.

Thanks, but what is your opinion about which of the combinations we
need to add?