Fix QRegularExpression API misuse in ElementsLocation::setXml (Qt6 path)

The Qt6 branch of the #if QT_VERSION guard swapped QRegExp for
QRegularExpression but kept calling QRegExp-only methods
(exactMatch()/cap()), which QRegularExpression doesn't have.
Use the correct QRegularExpression API instead: match() returns
a QRegularExpressionMatch, tested with hasMatch() and read with
captured(n).

sources/ElementsCollection/elementslocation.cpp

@@ -804,14 +804,15 @@ bool ElementsLocation::setXml(const QDomDocument &xml_document) const
 
 			QString			   path_ = collectionPath(false);
 			QRegularExpression rx("^(.*)/(.*\\.elmt)$");
+			QRegularExpressionMatch match = rx.match(path_);
 
-			if (rx.exactMatch(path_))
+			if (match.hasMatch())
 			{
 				return project()
 					->embeddedElementCollection()
 					->addElementDefinition(
-						rx.cap(1),
-						rx.cap(2),
+						match.captured(1),
+						match.captured(2),
 						xml_document.documentElement());
 			}
 			else