main: SDL_AppQuit() now reports the result value.

Fixes #10994.

examples/renderer/17-read-pixels/read-pixels.c

@@ -167,7 +167,7 @@ SDL_AppResult SDL_AppIterate(void *appstate)
 }
 
 /* This function runs once at shutdown. */
-void SDL_AppQuit(void *appstate)
+void SDL_AppQuit(void *appstate, SDL_AppResult result)
 {
     SDL_DestroyTexture(converted_texture);
     SDL_DestroyTexture(texture);