Enable high DPI support

Code copied from kate repo.

kcolorchooser.cpp

@@ -44,6 +44,8 @@ static const char description[] =
 	
 int main(int argc, char *argv[])
 {
+  QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling, true);
+  QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps, true);
   QApplication app(argc, argv);
   KLocalizedString::setApplicationDomain("kcolorchooser");
   KAboutData aboutData(QStringLiteral("kcolorchooser"), i18n("KColorChooser"),
@@ -54,7 +56,6 @@ int main(int argc, char *argv[])
   aboutData.setTranslator(i18nc("NAME OF TRANSLATORS", "Your names"), i18nc("EMAIL OF TRANSLATORS", "Your emails"));
   KAboutData::setApplicationData(aboutData);
 
-
   QCommandLineParser parser;
   parser.setSingleDashWordOptionMode(QCommandLineParser::ParseAsLongOptions);
   aboutData.setupCommandLine(&parser);