fix(elastic-docs): Fix elastic launch doc (#62378)
Summary:
The documentation link should be https://pytorch.org/docs/stable/elastic/run.html
Pull Request resolved: https://github.com/pytorch/pytorch/pull/62378
Reviewed By: aivanou
Differential Revision: D30002830
Pulled By: kiukchung
fbshipit-source-id: 34b434acaa10222561df43f6397a2420eef02015
