Number of search results in the region search

[LeandraH]

Is your feature request related to a problem? Please describe.
We have added a line to our content search for the number of search results, and an announcement for screen readers. We haven't done anything like that for our regions search. Maybe we should?

Describe the solution you'd like
When going to the regions search in web or native, after I start typing, I want to see how many results match my query. I also want an assertive announcement for screen readers if there are no search results.

We could also look into how much of that is duplicated between the content search and the regions search, and if we can combine more things.

Describe alternatives you've considered
We could leave it the way it is because nobody has complained about it so far.

Additional context
Discussed in #3006

[LeandraH]

Showing the number of region results has been implemented already, and I'll add the feedback for the screen reader in #3006