Update ExecuTorchError.h (#11007)

Author: shoumikhin

extension/apple/ExecuTorch/Exported/ExecuTorchError.h

@@ -62,7 +62,9 @@ NSString *ExecuTorchErrorDescription(ExecuTorchErrorCode code)
  * @param code The ExecuTorchErrorCode to wrap.
  * @return An NSError with ExecuTorchErrorDomain, the specified code, and a localized description.
  */
-FOUNDATION_EXPORT NSError *ExecuTorchErrorWithCode(ExecuTorchErrorCode code)
+FOUNDATION_EXPORT
+__attribute__((deprecated("This API is experimental.")))
+NSError *ExecuTorchErrorWithCode(ExecuTorchErrorCode code)
     NS_SWIFT_NAME(Error(code:));
 
 NS_ASSUME_NONNULL_END