feat(sdk): add documentation for order notes

src/documentation/50.php-sdk.md

@@ -646,8 +646,7 @@ $savedOrderCollection = $orderCollection->save();
 ### Adding order notes to an order
 
 It is possible to add notes to an order. These notes are visible in the backoffice.
-A note can be either a customer note or a webshop note. A customer note is
-always created in the checkout process and a webshop note can be created in the
+A note can be either a customer note or a webshop note. A webshop note can be created in the
 admin panel of an e-commerce platform.
 
 To add a note to an order, simply create