Remove all Qt version checks and branches for <5.15.12 as such versions are no longer supported.

sources/conductornumexport.cpp

@@ -72,14 +72,8 @@ bool ConductorNumExport::toCsv()
 		if (file.open(QIODevice::WriteOnly | QIODevice::Text))
 		{
 			QTextStream stream(&file);
-#if QT_VERSION < QT_VERSION_CHECK(5, 15, 0)	// ### Qt 6: remove
-			stream << wiresNum() << endl;
-#else
-#if TODO_LIST
-#pragma message("@TODO remove code for QT 5.15 or later")
-#endif
+
 			stream << wiresNum() << &Qt::endl(stream);
-#endif
 		}
 		else {
 			return false;