message: fix algorithm ReferenceError
diff: @@ -176,7 +176,7 @@ function textForHistoryVisibilityEvent(event) {
  function textForEncryptionEvent(event) {
  var senderName = event.sender ? event.sender.name : event.getSender();
  - return _t('%(senderName)s turned on end-to-end encryption (algorithm %(algorithm)s)', {senderName: senderName, algorithm: algorithm});
  + return _t('%(senderName)s turned on end-to-end encryption (algorithm %(algorithm)s)', {senderName: senderName, algorithm: event.getContent().algorithm});
  }
  // Currently will only display a change if a user's power level is changed
  