bug#53181: Live preview of regexp replace

[Juri Linkov]

>> This is exactly what Augusto is currently doing in bug#53126.
>
> I checked it and it's not the same. It says:
>
> " the highlighting and count of matches as one types a regexp or string to
> replace in `query-replace{-regexp}'."
>
> So it may do the first part, the highlighting of the regexp pattern while 
> typing,
> but it does not seem to do the second part, that is showing the replacement 
> effects
> in the buffer immediately as the user types the replacement text or pattern.
>
> The second part is just as important, because that shows if the actual 
> replacement
> is correct or it needs some tweaking before starting replacing.

Augusto is porting the package anzu to the core, and anzu implemented
the second part that shows the replacement effects immediately:

https://github.com/emacsorphanage/anzu.git