QmlDesigner: Fix a typo in a property editor label

Change-Id: I1b1cd8f402d379fc6db023ba1225757a7ca1099f
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@theqtcompany.com>

share/qtcreator/qmldesigner/propertyEditorQmlSources/HelperWidgets/FlickableSection.qml

@@ -51,7 +51,7 @@ Section {
             }
 
             Label {
-                text: "W"
+                text: "H"
                 width: 12
             }