Try to turn off `Provide a menu link` in `Menu settings` of your webform and to add menu link to webform page in your menu, `/admin/structure/menu > list links (of your menu) > Add link` instead.

If this doesn't work you can override themable output in your theme template.php file or in a custom module. Look at [this post][1].


  [1]: http://stackoverflow.com/questions/5019285/drupal-character-entity-in-menu-link-title