This link pops up an alert message:
The suggestion text (parameter to 'mediasearch-did-you-mean') is not HTML-escaped. You have to use 'intitle:' search operator in the query to exploit it (maybe some others also work), otherwise the search engine will "autocorrect" all of your code.
(I was testing things because the HTML-escaping issues in https://gerrit.wikimedia.org/r/c/mediawiki/extensions/MediaSearch/+/722974 made me think. But this is not actually related to any code changed in that patch.)