- Note that the database upgrade tool must be run after loading this commit to ensure that the shortlinks table's hash column is correctly populated.

(cherry picked from commit 7732da3c)

Otherwise this would depend on other facets being enabled.

- Includes expanded test coverage.

- Thanks to Leila Gonzales for the fix.
- See https://github.com/stamen/maps.stamen.com/issues/167 for details.

Also adds a missing parameter.

- Include quotes in search terms to improve accuracy
- Ensure correct URL encoding
- Add subject to list of search types

This fixes "Required parameter $limit follows optional parameter $page" error with PHP 8.