SDL_audio.h: Fixed typos in docs.

(cherry picked from commit 85435d5a149c48c244b019c4b6ed684dc9424792)

include/SDL3/SDL_audio.h

@@ -1717,7 +1717,7 @@ typedef void (SDLCALL *SDL_AudioStreamCallback)(void *userdata, SDL_AudioStream
  * audio to the stream during this call; if needed, the request that triggered
  * this callback will obtain the new data immediately.
  *
- * The callback's `approx_request` argument is roughly how many bytes of
+ * The callback's `additional_amount` argument is roughly how many bytes of
  * _unconverted_ data (in the stream's input format) is needed by the caller,
  * although this may overestimate a little for safety. This takes into account
  * how much is already in the stream and only asks for any extra necessary to
@@ -1762,7 +1762,7 @@ extern SDL_DECLSPEC bool SDLCALL SDL_SetAudioStreamGetCallback(SDL_AudioStream *
  * The callback can (optionally) call SDL_GetAudioStreamData() to obtain audio
  * from the stream during this call.
  *
- * The callback's `approx_request` argument is how many bytes of _converted_
+ * The callback's `additional_amount` argument is how many bytes of _converted_
  * data (in the stream's output format) was provided by the caller, although
  * this may underestimate a little for safety. This value might be less than
  * what is currently available in the stream, if data was already there, and