Merge #3904

3904: Sort by lexicographic order after normalization r=dureuill a=dureuill

# Pull Request

## Related issue
Fixes https://github.com/meilisearch/meilisearch/issues/3893

## What does this PR do?
- Re-sort stop words after normalization so they're not sent out-of-order to the FST


Co-authored-by: Louis Dureuil <louis@meilisearch.com>

milli/src/update/settings.rs

@@ -425,13 +425,14 @@ impl<'a, 't, 'u, 'i> Settings<'a, 't, 'u, 'i> {
                 let current = self.index.stop_words(self.wtxn)?;
 
                 // Apply an unlossy normalization on stop_words
-                let stop_words = stop_words
+                let stop_words: BTreeSet<String> = stop_words
                     .iter()
-                    .map(|w| w.as_str().normalize(&Default::default()).into_owned());
+                    .map(|w| w.as_str().normalize(&Default::default()).into_owned())
+                    .collect();
 
                 // since we can't compare a BTreeSet with an FST we are going to convert the
                 // BTreeSet to an FST and then compare bytes per bytes the two FSTs.
-                let fst = fst::Set::from_iter(stop_words)?;
+                let fst = fst::Set::from_iter(stop_words.into_iter())?;
 
                 // Does the new FST differ from the previous one?
                 if current