chore: changes in wording and code

Author: php-schubser

new_files/admin/includes/extra/css/fs_dutch_language_package.css.php

@@ -1,7 +1,6 @@
 <?php
 defined( '_VALID_XTC' ) or die( 'Direct Access to this location is not allowed.' );
 ?>
-
 <style>
 .disabled_button {
   opacity: 0.5;

new_files/admin/includes/modules/invoice_number/dutch/invoice_number.php

@@ -1,4 +1,3 @@
 <?php 
 define('BUTTON_BILL', 'Nieuw factuurnummer');
-define('NOT_ASSIGNED', 'Nog niet toegewezen!');
-?>
+define('NOT_ASSIGNED', 'Nog niet toegewezen!');