Merge #3824

3824: Changes the way words are counted in the word count DB r=ManyTheFish a=dureuill

# Pull Request

## Related issue

Fixes https://github.com/meilisearch/meilisearch/issues/3823

## What does this PR do?

- Apply offset when parsing query that is consistent with the indexing

### DB breaking changes

- Count the number of words in `field_id_word_count_docids`
- raise limit of word count for storing the entry in the DB from 10 to 30

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

milli/src/search/new/query_term/parse_query.rs

@@ -79,7 +79,7 @@ pub fn located_query_terms_from_tokens(
             TokenKind::Separator(separator_kind) => {
                 // add penalty for hard separators
                 if let SeparatorKind::Hard = separator_kind {
-                    position = position.wrapping_add(1);
+                    position = position.wrapping_add(7);
                 }
 
                 phrase = 'phrase: {

milli/src/update/index_documents/extract/extract_fid_word_count_docids.rs

@@ -1,6 +1,6 @@
 use std::collections::HashMap;
 use std::fs::File;
-use std::{cmp, io};
+use std::io;
 
 use grenad::Sorter;
 
@@ -54,11 +54,10 @@ pub fn extract_fid_word_count_docids<R: io::Read + io::Seek>(
         }
 
         for position in read_u32_ne_bytes(value) {
-            let (field_id, position) = relative_from_absolute_position(position);
-            let word_count = position as u32 + 1;
+            let (field_id, _) = relative_from_absolute_position(position);
 
             let value = document_fid_wordcount.entry(field_id as FieldId).or_insert(0);
-            *value = cmp::max(*value, word_count);
+            *value += 1;
         }
     }
 
@@ -83,7 +82,7 @@ fn drain_document_fid_wordcount_into_sorter(
     let mut key_buffer = Vec::new();
 
     for (fid, count) in document_fid_wordcount.drain() {
-        if count <= 10 {
+        if count <= 30 {
             key_buffer.clear();
             key_buffer.extend_from_slice(&fid.to_be_bytes());
             key_buffer.push(count as u8);