bug#53181: Live preview of regexp replace

[Juri Linkov]

> I've been using the visual regexp package for a while and it's really
> useful:
>
> https://github.com/benma/visual-regexp.el
>
> It would improve the core emacs experience if the built in regexp replace
> did this as well.  When constructing a regexp replace it's really useful to
> see the match and the capturing groups instantly in the buffer, and also
> the resulting text on the fly when typing the replacement.  It spares you
> from doing several test-fix cycles until you get the regexp replacement
> right, because you have an instant live preview of everything in the target
> buffer.
>
> Adding this feature would benefit the default regexp replace experience a lot.

This is exactly what Augusto is currently doing in bug#53126.