Add more to SimpleXMLElement stub

stubs/CoreGenericClasses.phpstub

@@ -2217,10 +2217,69 @@ final class WeakReference
 
 class SimpleXMLElement implements \Stringable, \Countable, \RecursiveIterator
 {
+    /** @return array */
+    public function getNamespaces(bool $recursive = false)
+    {
+    }
+    /** @return array|false */
+    public function getDocNamespaces(bool $recursive = false, bool $fromRoot = true)
+    {
+    }
+    /** @return SimpleXMLIterator */
+    public function children(?string $namespaceOrPrefix = null, bool $isPrefix = false)
+    {
+    }
+    /** @return SimpleXMLIterator */
+    public function attributes(?string $namespaceOrPrefix = null, bool $isPrefix = false)
+    {
+    }
+    public function __construct(string $data, int $options = 0, bool $dataIsURL = false, string $namespaceOrPrefix = "", bool $isPrefix = false)
+    {
+    }
+    /** @return SimpleXMLElement */
+    public function addChild(string $qualifiedName, ?string $value = null, ?string $namespace = null)
+    {
+    }
+    /** @return SimpleXMLElement */
+    public function addAttribute(string $qualifiedName, ?string $value = null, ?string $namespace = null)
+    {
+    }
+    /** @return string */
+    public function getName()
+    {
+    }
+    public function __toString() : string
+    {
+    }
+    /** @return int */
+    public function count()
+    {
+    }
+    /** @return void */
+    public function rewind()
+    {
+    }
+    /** @return bool */
+    public function valid()
+    {
+    }
+
     /** @return SimpleXMLElement */
     public function current()
     {
     }
+    /** @return string|false */
+    public function key()
+    {
+    }
+    /** @return void */
+    public function next()
+    {
+    }
+    /** @return bool */
+    public function hasChildren()
+    {
+    }
     /** @return SimpleXMLElement|null */
     public function getChildren()
     {