Fix typo in CyclicLR docs (#21021)
Summary:
Fixes a typo in the CyclicLR docs by adding the lr_scheduler directory and puts in other required arguments.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21021
Differential Revision: D15530109
Pulled By: soumith
fbshipit-source-id: 98781bdab8d82465257229e50fa3bd0015da1286
