to keep type-hinting compatibility, the json serialization visitor st…

…ill extends the generic serializer even if overrides all of its logic.

In the future releases, the generic serialization visitor will have to be just removed

src/JMS/Serializer/JsonSerializationVisitor.php

@@ -22,7 +22,7 @@
 use JMS\Serializer\Exception\InvalidArgumentException;
 use JMS\Serializer\Metadata\PropertyMetadata;
 
-class JsonSerializationVisitor extends AbstractVisitor
+class JsonSerializationVisitor extends GenericSerializationVisitor
 {
     private $options = 0;