Fix the lint error in transformer doc. (#25027)
Summary:
Fix the lint error in transformer doc.
https://github.com/pytorch/pytorch/pull/24837
Pull Request resolved: https://github.com/pytorch/pytorch/pull/25027
Differential Revision: D16963508
Pulled By: zhangguanheng66
fbshipit-source-id: 3f70e32c74d2319ffb8e2143d3181ed38e62067d
