macOS: Correct QNSPanelContentsWrapper @end marker placement

The incorrect "scoping" of q_IOObjectRetain and q_IOObjectRelease
luckily did not affect their functionality as QIOType helpers.

Pick-to: 6.2
Change-Id: I9b9c2312464c7e6f8e2d2a5856e35efa99ec0c41
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

src/plugins/platforms/cocoa/qcocoahelpers.mm

@@ -495,6 +495,8 @@ QT_END_NAMESPACE
     [super layout];
 }
 
+@end // QNSPanelContentsWrapper
+
 // -------------------------------------------------------------------------
 
 io_object_t q_IOObjectRetain(io_object_t obj)
@@ -550,4 +552,3 @@ QDebug operator<<(QDebug debug, SEL selector)
     debug << NSStringFromSelector(selector);
     return debug;
 }
-@end