minor #18905 Update entity.rst (toci-to-ci)

This PR was submitted for the 6.3 branch but it was merged into the 5.4 branch instead.

Discussion
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Update entity.rst

query_builder option - more clear explained

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a938b6d Update entity.rst

Author: javiereguiluz

reference/forms/types/entity.rst

@@ -49,7 +49,7 @@ Using a Custom Query for the Entities
 
 If you want to create a custom query to use when fetching the entities
 (e.g. you only want to return some entities, or need to order them), use
-the `query_builder`_ option::
+the `query_builder`_ option. Please note, that `query_builder` is used to compose data, not fetch real final results::
 
     use App\Entity\User;
     use Doctrine\ORM\EntityRepository;