JsonPointer: Fix phpdoc type hint for $default

Author: dontub

src/JsonPointer.php

@@ -116,7 +116,7 @@ public function __toString(): string
     /**
      * @param $data
      * @param array|null $path
-     * @param null $default
+     * @param mixed $default
      * @return mixed
      */
     public function data($data, ?array $path = null, $default = null)
@@ -252,7 +252,7 @@ public static function parse(string $pointer, bool $decode = true): ?self
      * @param $data
      * @param array|null $path
      * @param bool $fragment
-     * @param null $default
+     * @param mixed $default
      * @return mixed
      */
     public static function getData($data, ?array $path = null, bool $fragment = false, $default = null)
@@ -407,4 +407,4 @@ public static function createRelative(int $level, array $path = [], int $shift =
     {
         return new self($path, $level, $shift, $fragment);
     }
-}
+}