SPEC-25: Add details on how to prune redacted events.
SPEC-25: Add details on how to prune redacted events.

SPEC-25 #comment I've added the details of what the server should do on
receipt of a redaction event. In reality it can do whatever it wants,
and its probably a reasonable implementation to flag it up to a server
admin for verification before actually redacting an event.

illicitonion/synapse,matrix-org/synapse,TribeMedia/synapse,rzr/synapse,iot-factory/synapse,TribeMedia/synapse,illicitonion/synapse,rzr/synapse,TribeMedia/synapse,iot-factory/synapse,rzr/synapse,matrix-org/synapse,illicitonion/synapse,iot-factory/synapse,TribeMedia/synapse,matrix-org/synapse,matrix-org/synapse,matrix-org/synapse,TribeMedia/synapse,iot-factory/synapse,howethomas/synapse,howethomas/synapse,howethomas/synapse,howethomas/synapse,iot-factory/synapse,rzr/synapse,illicitonion/synapse,howethomas/synapse,illicitonion/synapse,rzr/synapse,matrix-org/synapse