When searching in OPAC, highlighting does not work if the search string contains diacritics

[Eva Cerninakova]

If the search query contains a term with a diacritic, the term is not highlighted in the search results. The issue affects both the staff client and the OPAC, no matter what interface language is used or what the search phrase language is
 (see the attachments).

If the search query is longer and contains both accented and unaccented words, only the unaccented words are highlighted.

I tested this in Evergreen 3.11 and on the Bug Squashing week test servers https://bugsquash3.mobiusconsortium.org and https://terran-main.gapines.org/; however, I spotted the same behavior in the older non-bootstrap OPAC. I searched for French and Czech words with diacritics in the Czech, French, and English interfaces.