Better to document "-widgets" argument in QUICK_TEST_MAIN and etc

int quick_test_main_with_setup(int argc, char **argv, const char *name, const char *sourceDir, QObject *setup)
{
    // Peek at arguments to check for '-widgets' argument
#ifdef QT_QMLTEST_WITH_WIDGETS
    bool withWidgets = false;
    for (int index = 1; index < argc; ++index) {
        if (strcmp(argv[index], "-widgets") == 0) {
            withWidgets = true;
            break;
        }
    }
#endif