enable high dpi scaling in Qt Linguist

Hello,

could you add high dpi support for Qt Linguist? It seems that its not there yet.

You just have to add these three lines to the main() function to make it work.

#if (QT_VERSION >= QT_VERSION_CHECK(5, 6, 0))  

   QApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

#endif