[Doc] fix broken link
Fixes https://github.com/huggingface/transformers/issues/21275 
I can confirm the link at least works in https://moon-ci-docs.huggingface.co/docs/transformers/pr_21276/en/main_classes/text_generation

cc @ydshieh 💯 

_The documentation is not available anymore as the PR was closed or merged._