Add missing use in code

Author: npotier

core/filters.md

@@ -145,6 +145,8 @@ In the following example, we will see how to allow the filtering of a list of e-
 namespace App\Entity;
 
 use ApiPlatform\Core\Annotation\ApiResource;
+use ApiPlatform\Core\Annotation\ApiFilter;
+use ApiPlatform\Core\Bridge\Doctrine\Orm\Filter\SearchFilter;
 
 /**
  * @ApiResource()