minor #13586 [DX][Config] Changed return type definition for some methods of NodeDefinition (Strate)

This PR was submitted for the 2.7 branch but it was merged into the 2.3 branch instead (closes #13586).

Discussion
----------

[DX][Config] Changed return type definition for some methods of NodeDefinition

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #12280
| License       | MIT

Discussed in #12280

Commits
-------

89ca585 Changed return type definition for some methods of NodeDefinition

Author: fabpot

src/Symfony/Component/Config/Definition/Builder/EnumNodeDefinition.php

@@ -22,6 +22,11 @@ class EnumNodeDefinition extends ScalarNodeDefinition
 {
     private $values;
 
+    /**
+     * @param array $values
+     *
+     * @return EnumNodeDefinition|$this
+     */
     public function values(array $values)
     {
         $values = array_unique($values);

src/Symfony/Component/Config/Definition/Builder/NodeDefinition.php

@@ -59,7 +59,7 @@ public function __construct($name, NodeParentInterface $parent = null)
      *
      * @param NodeParentInterface $parent The parent
      *
-     * @return NodeDefinition
+     * @return NodeDefinition|$this
      */
     public function setParent(NodeParentInterface $parent)
     {
@@ -73,7 +73,7 @@ public function setParent(NodeParentInterface $parent)
      *
      * @param string $info The info text
      *
-     * @return NodeDefinition
+     * @return NodeDefinition|$this
      */
     public function info($info)
     {
@@ -85,7 +85,7 @@ public function info($info)
      *
      * @param string|array $example
      *
-     * @return NodeDefinition
+     * @return NodeDefinition|$this
      */
     public function example($example)
     {
@@ -98,7 +98,7 @@ public function example($example)
      * @param string $key
      * @param mixed  $value
      *
-     * @return NodeDefinition
+     * @return NodeDefinition|$this
      */
     public function attribute($key, $value)
     {
@@ -149,7 +149,7 @@ public function getNode($forceRootNode = false)
      *
      * @param mixed $value The default value
      *
-     * @return NodeDefinition
+     * @return NodeDefinition|$this
      */
     public function defaultValue($value)
     {
@@ -162,7 +162,7 @@ public function defaultValue($value)
     /**
      * Sets the node as required.
      *
-     * @return NodeDefinition
+     * @return NodeDefinition|$this
      */
     public function isRequired()
     {
@@ -176,7 +176,7 @@ public function isRequired()
      *
      * @param mixed $value
      *
-     * @return NodeDefinition
+     * @return NodeDefinition|$this
      */
     public function treatNullLike($value)
     {
@@ -190,7 +190,7 @@ public function treatNullLike($value)
      *
      * @param mixed $value
      *
-     * @return NodeDefinition
+     * @return NodeDefinition|$this
      */
     public function treatTrueLike($value)
     {
@@ -204,7 +204,7 @@ public function treatTrueLike($value)
      *
      * @param mixed $value
      *
-     * @return NodeDefinition
+     * @return NodeDefinition|$this
      */
     public function treatFalseLike($value)
     {
@@ -216,7 +216,7 @@ public function treatFalseLike($value)
     /**
      * Sets null as the default value.
      *
-     * @return NodeDefinition
+     * @return NodeDefinition|$this
      */
     public function defaultNull()
     {
@@ -226,7 +226,7 @@ public function defaultNull()
     /**
      * Sets true as the default value.
      *
-     * @return NodeDefinition
+     * @return NodeDefinition|$this
      */
     public function defaultTrue()
     {
@@ -236,7 +236,7 @@ public function defaultTrue()
     /**
      * Sets false as the default value.
      *
-     * @return NodeDefinition
+     * @return NodeDefinition|$this
      */
     public function defaultFalse()
     {
@@ -256,7 +256,7 @@ public function beforeNormalization()
     /**
      * Denies the node value being empty.
      *
-     * @return NodeDefinition
+     * @return NodeDefinition|$this
      */
     public function cannotBeEmpty()
     {
@@ -284,7 +284,7 @@ public function validate()
      *
      * @param bool $deny Whether the overwriting is forbidden or not
      *
-     * @return NodeDefinition
+     * @return NodeDefinition|$this
      */
     public function cannotBeOverwritten($deny = true)
     {