Autocomplete doesn't work if your search contains diactrictics

[AoNoOokami]

Describe the issue
Autocomplete doesn't work if your search contains diactrictics (try: réalité and realite)

To Reproduce
Steps to reproduce the behavior:

1. Go to homepage
2. Search with 'realite' keyword
3. There is no autocomplete, no suggestions of result

Expected behavior
Autocomplete should work with diactrictics in the search

Software version
ilsdev.test.rero.ch
647a7f3
rero/rero-ils-ui@30e8cdd

[zannkukai]

Search with diacritics seems works well.
I had some issues with L' prefix before diacritics words.
Search with école return no result, search with l'école return 1 result.
Search with tête return 1 result (as expected)
Maybe the "apostrophe" isn't yet considered at a word separator into ES analyzer ?

Not an expert but it seems than basic standard tokenizer doesn't split words. Maybe it should be better to use icu_tokenizer ? There is a french blog post introducing some french specification here : https://jolicode.com/blog/construire-un-bon-analyzer-francais-pour-elasticsearch

[zannkukai]

Should a request with tete return tête results ?

[pronguen]

Seems to be solved: the suggestions include the diacritics. But the highlighted text in each suggestion does not.