Allow to update -> Allow updating (#6131)

src/pretix/base/settings.py

@@ -1276,7 +1276,7 @@ DEFAULTS = {
         'serializer_class': serializers.BooleanField,
         'write_permission': 'event.settings.invoicing:write',
         'form_kwargs': dict(
-            label=_("Allow to update existing invoices"),
+            label=_("Allow updating existing invoices"),
             help_text=_("By default, invoices can never again be changed once they are issued. In most countries, we "
                         "recommend to leave this option turned off and always issue a new invoice if a change needs "
                         "to be made."),