Fix return of uninitialized pointer in guiloader example

Signed-off-by: Sander Visser <github@visser.se>
Change-Id: I7e23402562bd560d55bb811e5e61cca4fcfe247d
Reviewed-by: Jean-Michaël Celerier <jean-michael.celerier@kdab.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

doc/src/snippets/quiloader/main.cpp

@@ -57,7 +57,7 @@
 QWidget *loadCustomWidget(QWidget *parent)
 {
     QUiLoader loader;
-    QWidget *myWidget;
+    QWidget *myWidget = nullptr;
 
     QStringList availableWidgets = loader.availableWidgets();