docs: Remove a redundant comment.

(The wiki will link to this symbol, we don't have to explicitly mention it.)

include/SDL3/SDL_keyboard.h

@@ -174,8 +174,7 @@ extern SDL_DECLSPEC void SDLCALL SDL_ResetKeyboard(void);
 /**
  * Get the current key modifier state for the keyboard.
  *
- * \returns an OR'd combination of the modifier keys for the keyboard. See
- *          SDL_Keymod for details.
+ * \returns an OR'd combination of the modifier keys for the keyboard.
  *
  * \threadsafety It is safe to call this function from any thread.
  *