WinRT: Corrected header file guard comment.

src/video/winrt/SDL_winrtgamebar_cpp.h

@@ -30,6 +30,6 @@ extern void WINRT_InitGameBar(_THIS);
 extern void WINRT_QuitGameBar(_THIS);
 #endif
 
-#endif /* _SDL_winrtmouse_h */
+#endif /* _SDL_winrtgamebar_h */
 
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