* Raise a dedicated `InvalidEventSignatureError` from `_check_sigs_on_pdu`
* Downgrade logging about redactions to DEBUG
this can be very spammy during a room join, and it's not very useful.
* Raise `InvalidEventSignatureError` from `_check_sigs_and_hash`
... and, more importantly, move the logging out to the callers.
* changelog
