Relevance is not accurate in boolean mode

[abibby]

When you are using boolean mode to search the relevance uses natural language mode.

I think the issue is in src/Engines/Modes/Boolean.php

 public function buildSelectColumns(Builder $builder)
 {
     $indexFields = implode(',',  $this->modelService->setModel($builder->model)->getFullTextIndexFields());
 
-    return "*, MATCH($indexFields) AGAINST(? IN NATURAL LANGUAGE MODE) AS relevance";
+    return "*, MATCH($indexFields) AGAINST(? IN BOOLEAN MODE) AS relevance";
 }