remove a non-critical XXX note

www/common/common-ui-elements.js

@@ -1569,7 +1569,6 @@ define([
                 button = $('<button>', {
                     title: Messages.printButtonTitle2,
                     'class': "fa fa-print cp-toolbar-icon-print",
-                // XXX people don't realize this does PDF (https://github.com/xwiki-labs/cryptpad/issues/357#issuecomment-640711724)
                 }).append($('<span>', {'class': 'cp-toolbar-drawer-element'}).text(Messages.printText));
                 break;
             case 'history':