message: Document behaviour of showReadReceipts=false for sent receipts
diff: @@ -498,6 +498,9 @@ export default class MessagePanel extends React.Component {
  let prevEvent = null; // the last event we showed
  + // Note: the EventTile might still render a "sent/sending receipt" independent of
  + // this information. When not providing read receipt information, the tile is likely
  + // to assume that sent receipts are to be shown more often.
  this._readReceiptsByEvent = {};
  if (this.props.showReadReceipts) {
  this._readReceiptsByEvent = this._getReadReceiptsByShownEvent();
  