Sync SDL3 wiki -> header

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include/SDL3/SDL_asyncio.h

@@ -338,10 +338,10 @@ extern SDL_DECLSPEC bool SDLCALL SDL_WriteAsyncIO(SDL_AsyncIO *asyncio, void *pt
  * close the file immediately, then check for all results later. This function
  * will not block until the tasks have completed.
  *
- * Once this function returns non-NULL, `asyncio` is no longer valid,
- * regardless of any future outcomes. Any completed tasks might still contain
- * this pointer in their SDL_AsyncIOOutcome data, in case the app was using
- * this value to track information, but it should not be used again.
+ * Once this function returns true, `asyncio` is no longer valid, regardless
+ * of any future outcomes. Any completed tasks might still contain this
+ * pointer in their SDL_AsyncIOOutcome data, in case the app was using this
+ * value to track information, but it should not be used again.
  *
  * If this function returns false, the close wasn't started at all, and it's
  * safe to attempt to close again later.