doxygen: Removed some cruft that accumulated during wiki migration.

include/SDL_shape.h

@@ -117,7 +117,7 @@ typedef struct SDL_WindowShapeMode {
  *         not reference a valid shaped window.
  *
  * \sa SDL_WindowShapeMode
- * \sa [[SDL_GetShapedWindowMode.]]
+ * \sa SDL_GetShapedWindowMode
  */
 extern DECLSPEC int SDLCALL SDL_SetWindowShape(SDL_Window *window,SDL_Surface *shape,SDL_WindowShapeMode *shape_mode);
 

include/SDL_video.h

@@ -1686,7 +1686,6 @@ extern DECLSPEC SDL_bool SDLCALL SDL_GL_ExtensionSupported(const char
  *
  * \sa SDL_GL_GetAttribute
  * \sa SDL_GL_SetAttribute
- * \sa [[<!-- #Remove this section if empty -->]]
  */
 extern DECLSPEC void SDLCALL SDL_GL_ResetAttributes(void);