Update docs/query-builder.txt

Co-authored-by: Andreas Braun <[email protected]>

Author: GromNaN

docs/query-builder.txt

@@ -306,7 +306,7 @@ is less than 85:
 
    User::where('results', 'elemMatch', ['gte' => 80, 'lt' => 85])->get();
 
-A sub-query builder can be to apply filter on documents.
+A closure can be used to create more complex sub-queries.
 
 The following query matches only those documents where the results array
 contains at least one element with both product equal to "xyz" and score