Fix several minor things in .circleci/README.md (#51724)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/51724
Reviewed By: walterddr
Differential Revision: D26252671
Pulled By: samestep
fbshipit-source-id: 53781c391e3b54f3896e88bce07f7ee66a19ac92
