Add generic types to traversable implementations

Author: derrabus

Definition.php

@@ -846,7 +846,7 @@ public function setAutowired(bool $autowired)
     /**
      * Gets bindings.
      *
-     * @return array|BoundArgument[]
+     * @return BoundArgument[]
      */
     public function getBindings()
     {

Dumper/PhpDumper.php

@@ -62,6 +62,9 @@ class PhpDumper extends Dumper
      */
     public const NON_FIRST_CHARS = 'abcdefghijklmnopqrstuvwxyz0123456789_';
 
+    /**
+     * @var \SplObjectStorage<Definition, Variable>|null
+     */
     private $definitionVariables;
     private $referenceVariables;
     private $variableCount;