Fix QLocal::decimalPoint() returns QString in Qt6

src/assets/model/assetparametermodel.cpp

@@ -37,15 +37,20 @@ AssetParameterModel::AssetParameterModel(std::unique_ptr<Mlt::Properties> asset,
     m_isAudio = assetXml.attribute(QStringLiteral("type")) == QLatin1String("audio");
 
     bool needsLocaleConversion = false;
-    QChar separator;
-    QChar oldSeparator;
+    QString separator;
+    QString oldSeparator;
     // Check locale, default effects xml has no LC_NUMERIC defined and always uses the C locale
     if (assetXml.hasAttribute(QStringLiteral("LC_NUMERIC"))) {
         QLocale effectLocale = QLocale(assetXml.attribute(QStringLiteral("LC_NUMERIC"))); // Check if effect has a special locale → probably OK
         if (QLocale::c().decimalPoint() != effectLocale.decimalPoint()) {
             needsLocaleConversion = true;
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
+            separator = QString(QLocale::c().decimalPoint());
+            oldSeparator = QString(effectLocale.decimalPoint());
+#else
             separator = QLocale::c().decimalPoint();
             oldSeparator = effectLocale.decimalPoint();
+#endif
         }
     }