Fix #163 -- Form to change orders (#191)

src/pretix/base/settings.py

@@ -191,6 +191,18 @@ of {total} {currency}. Please complete your payment before {date}.
 You can change your order details and view the status of your order at
 {url}
 
+Best regards,
+Your {event} team"""))
+    },
+    'mail_text_order_changed': {
+        'type': LazyI18nString,
+        'default': LazyI18nString.from_gettext(ugettext_noop("""Hello,
+
+your order for {event} has been changed.
+
+You can view the status of your order at
+{url}
+
 Best regards,
 Your {event} team"""))
     },