[DataPipe] Update deprecation warning (#71171)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/71171
Editing two warnings to more accurately portray the deprecation plan for the DataPipes
cc VitalyFedyunin ejguan NivekT
Test Plan: Imported from OSS
Reviewed By: ejguan
Differential Revision: D33535785
Pulled By: NivekT
fbshipit-source-id: b902aaa3637ade0886c86a57b58544ff7993fd91
