feat(strings): add new methods dd and dump

Author: Awilum

src/Strings.php

@@ -2750,7 +2750,7 @@ static function (&$value) use ($encoding): void {
      */
     public function dump(?callable $callback = null): self
     {
-        $callback ? $callback($this->strings) : print_r($this->strings);
+        $callback ? $callback($this->toString()) : print_r($this->toString());
 
         return $this;
     }