Add admin handler to list of handlers used for background tasks (#17847)

Fixes #17823

While we're at it, makes a change where the redactions are sent as the
admin if the user is not a member of the server (otherwise these fail
with a "User must be our own" message).

1 files changed, 3 insertions, 0 deletions

diff --git a/docs/admin_api/user_admin_api.md b/docs/admin_api/user_admin_api.md

index cb38e26005..96a2994b7b 100644
--- a/docs/admin_api/user_admin_api.md
+++ b/docs/admin_api/user_admin_api.md
@@ -1365,6 +1365,9 @@ _Added in Synapse 1.72.0._
 
 ## Redact all the events of a user
 
+This endpoint allows an admin to redact the events of a given user. There are no restrictions on redactions for a 
+local user. By default, we puppet the user who sent the message to redact it themselves. Redactions for non-local users are issued using the admin user, and will fail in rooms where the admin user is not admin/does not have the specified power level to issue redactions. 
+
 The API is 
 ```
 POST /_synapse/admin/v1/user/$user_id/redact