message: Fix React warnings about missing key for edited messages
  This uses a fragment instead of an array to avoid the need for key attributes.
diff: @@ -410,7 +410,10 @@ export default class TextualBody extends React.Component {
  ref: this._content,
  });
  if (this.props.replacingEventId) {
  - body = [body, this._renderEditedMarker()];
  + body = <>
  + {body}
  + {this._renderEditedMarker()}
  + </>;
  }
  if (this.props.highlightLink) {
  