bug#29321: Isearch hit count

[Juri Linkov]

>> It's unclear how it should progress incrementally.  After starting
>> to type `C-6 C-s f' it can find the sixth next occurrence of "f".
>> To find the sixth next occurrence of "foo", it needs to search
>> non-incrementally.
>
> In what sense non-incrementally?  It would still do the same job as
> normal Isearch, after skipping the first 5 results.

To find the sixth occurrence of "foo", "foo" should be already
in the current search string before typing `C-6 C-s'.