qdbusxml2cpp: Drop extra QString()

This commit addresses a comment from the review of QTBUG-98434.

Drop the extra QString(), .arg can be called on _L1 as well.

Task-number: QTBUG-103100
Change-Id: I4891d42536f6ea413464bea78de4b82aa6363a11
Reviewed-by: Marc Mutz <marc.mutz@qt.io>

src/tools/qdbusxml2cpp/qdbusxml2cpp.cpp

@@ -284,7 +284,7 @@ static QString constRefArg(const QByteArray &arg)
     if (!arg.startsWith('Q'))
         return QLatin1StringView(arg + ' ');
     else
-        return QString("const %1 &"_L1).arg(QLatin1StringView(arg));
+        return "const %1 &"_L1.arg(QLatin1StringView(arg));
 }
 
 static QStringList makeArgNames(const QDBusIntrospection::Arguments &inputArgs,