Fixed a few warnings that show up with -Wdocumentation and -Wdocumentation-unknown-command, patch contributed by Sylvain

include/SDL_hints.h

@@ -780,6 +780,11 @@ extern DECLSPEC const char * SDLCALL SDL_GetHint(const char *name);
  */
 extern DECLSPEC SDL_bool SDLCALL SDL_GetHintBoolean(const char *name, SDL_bool default_value);
 
+/**
+ * \brief type definition of the hint callback function.
+ */
+typedef void (*SDL_HintCallback)(void *userdata, const char *name, const char *oldValue, const char *newValue);
+
 /**
  *  \brief Add a function to watch a particular hint
  *
@@ -787,7 +792,6 @@ extern DECLSPEC SDL_bool SDLCALL SDL_GetHintBoolean(const char *name, SDL_bool d
  *  \param callback The function to call when the hint value changes
  *  \param userdata A pointer to pass to the callback function
  */
-typedef void (*SDL_HintCallback)(void *userdata, const char *name, const char *oldValue, const char *newValue);
 extern DECLSPEC void SDLCALL SDL_AddHintCallback(const char *name,
                                                  SDL_HintCallback callback,
                                                  void *userdata);