Clarify that the SDL_GetStringRule means that SDL will automatically free the memory later.

include/SDL3/SDL_version.h

@@ -163,7 +163,7 @@ extern SDL_DECLSPEC int SDLCALL SDL_GetVersion(void);
  * You shouldn't use this function for anything but logging it for debugging
  * purposes. The string is not intended to be reliable in any way.
  *
- * The returned string follows the SDL_GetStringRule.
+ * The returned string follows the SDL_GetStringRule, and will be automatically freed later.
  *
  * \returns an arbitrary string, uniquely identifying the exact revision of
  *          the SDL library in use.