remove stale comment, we include vias now

src/components/views/context_menus/MessageContextMenu.js

@@ -327,7 +327,6 @@ export default class MessageContextMenu extends React.Component {
         if (this.props.permalinkCreator) {
             permalink = this.props.permalinkCreator.forEvent(this.props.mxEvent.getId());
         }
-        // XXX: if we use room ID, we should also include a server where the event can be found (other than in the domain of the event ID)
         const permalinkButton = (
             <IconizedContextMenuOption
                 iconClassName="mx_MessageContextMenu_iconPermalink"