QPageLayout::OutOfBoundsPolicy: add missing trailing comma

Task-number: QTBUG-125859
Change-Id: I7834a5bd0884ab23f83813a87e9c51ab34c10797
Reviewed-by: Ahmad Samir <a.samirh78@gmail.com>
(cherry picked from commit 68ee140d17233ae17d9728dc5967ddf125c21018)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/gui/painting/qpagelayout.h

@@ -42,7 +42,7 @@ public:
 
     enum class OutOfBoundsPolicy {
         Reject,
-        Clamp
+        Clamp,
     };
 
     QPageLayout();