Searches that include "al-" return no results in REST API

[nathangibson]

E.g.

• https://usaybia.net/api/search/persName?q=al-Malik returns 0 but should return same as https://usaybia.net/api/search/persName?q=Malik
• https://usaybia.net/api/search/persName?q=al-din returns 0 but should return ~ the same as https://usaybia.net/api/search/persName?q=din

"al-" is probably marked as a stopword, but then it should be filtered out rather than dropping the whole expression

[wsalesky]

Closing, this is the same issue as #81