Update object_mapper.rst

Fixed documentation for transfomrer inicialization.
Need to be new instance creation instance of class path

Author: tito10047

object_mapper.rst

@@ -375,7 +375,7 @@ Then, use this service to format the mapped property::
     class UserInput
     {
         // this property's value will be generated by the transformer
-        #[Map(target: 'fullName', transform: FullNameTransformer::class)]
+        #[Map(target: 'fullName', transform: new FullNameTransformer())]
         public string $firstName = '';
 
         public string $lastName = '';