Get records with specific selected select-type value

So I have a content type of regions:

```
regions:
name: Regions
singular_name: Region
fields:
r_id:
type: number
mode: integer
required: true
title:
type: text
class: large
required: true
slug:
type: slug
uses: r_id
record_template: region.twig
listing_template: regionList.twig
listing_records: 20
records_per_page: 20
```
And I have a contenttype of internships that uses the above:
```
internships:
name: Internships
singular_name: Internship
fields:
...
city:
type: select
label: City
values: regions/{title}
sort: title
autocomplete: true
required: true
...
relations:
...
...
```
In my webapp I need to filter entries by city. How do I write the filtering query to select all internships where selected city is exactly one of the list?

Start with the Bolt filtering/query documentation and the `internships.city` select configuration shown in the issue. Confirm the documented query syntax for matching one exact selected city, and record a working example whose results contain only matching internships.

Written by the indexing model from the issue text.