message: include fullstop fixup
diff: @@ -38,6 +38,7 @@ VoIP conference finished.
  %(senderName)s sent an invitation to %(targetDisplayName)s to join the room.
  %(senderName)s turned on end-to-end encryption (algorithm %(algorithm)s).
  %(senderName)s changed the power level of %(powerLevelDiffText)s.
  +For security, this session has been signed out. Please sign in again.
  EOT
  )];
  }
  