Doc: fix QDoc command in a tutorial

Change-Id: Id511edfce884130a7c93dc8f51eb156a10b5b73f
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@theqtcompany.com>

doc/src/qtquick/qtquick-app-tutorial.qdoc

@@ -57,7 +57,7 @@
     the QML file). The image appears in \uicontrol Resources. You can also use
     any other image or a QML type, instead.
 
-    \list a
+    \list 1
 
         \li In the \uicontrol Projects view, double-click the MainForm.ui.qml
             file to open it in \QMLD.