Enable HiDPI for customdialogs and spellcheckers examples

Task-number: QTBUG-75103
Change-Id: I8290ba268f30b26eafccabc889ad860e95c1bca2
Reviewed-by: Michal Klocek <michal.klocek@qt.io>

examples/webengine/customdialogs/main.cpp

@@ -66,6 +66,7 @@ typedef QGuiApplication Application;
 int main(int argc, char *argv[])
 {
     QCoreApplication::setOrganizationName("QtExamples");
+    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
     Application app(argc, argv);
     QtWebEngine::initialize();
 

examples/webenginewidgets/spellchecker/main.cpp

@@ -54,6 +54,7 @@
 int main(int argc, char *argv[])
 {
     QCoreApplication::setOrganizationName("QtExamples");
+    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
     QApplication app(argc, argv);
 
     WebView view;