Sync SDL3 wiki -> header

[ci skip]

include/SDL3/SDL_hints.h

@@ -4766,7 +4766,8 @@ extern SDL_DECLSPEC bool SDLCALL SDL_GetHintBoolean(const char *name, bool defau
  * A callback used to send notifications of hint value changes.
  *
  * This is called an initial time during SDL_AddHintCallback with the hint's
- * current value, and then again each time the hint's value changes.
+ * current value, and then again each time the hint's value changes. In the
+ * initial call, the current value is in both `oldValue` and `newValue`.
  *
  * \param userdata what was passed as `userdata` to SDL_AddHintCallback().
  * \param name what was passed as `name` to SDL_AddHintCallback().