bug#23484: 25.1.50; undo doesn't work properly in xref-query-replace-in-results

[Juri Linkov]

>> Why not using an original search string instead of ‘.*’ thus avoiding
>> tricks with isearch-filter-predicate/replace-re-search-function?
>
> A few reasons:
>
> - We don't actually save it.
> - Being able to replace _any_ regexp inside the matches is a feature
> (though maybe it's not going to be very popular).

Honestly speaking, the ‘.*’ thing is quite confusing.
More natural syntax is ‘\&’ like is used in e.g.
‘occur-read-primary-args’ to collect the entire match.