add shred_completed

src/pretix/base/services/shredder.py

@@ -176,6 +176,7 @@ def shred(self, event: Event, fileid: str, confirm_code: str, user: int=None, lo
                 _('Data shredding completed'),
                 'pretixbase/email/shred_completed.txt',
                 {
+                    'instance': settings.PRETIX_INSTANCE_NAME,
                     'user': user,
                     'organizer': event.organizer.name,
                     'event': str(event.name),

src/pretix/base/templates/pretixbase/email/shred_completed.txt

@@ -13,5 +13,5 @@ Start time: {{ start_time }} (new data added after this time might not have been
 
 Best regards,
 
-Your pretix team
+Your {{ instance }} team
 {% endblocktrans %}