[3.8] bpo-39427: Document -X opt options in the CLI --help and the man page (GH-18131) (GH-18133)

https://bugs.python.org/issue39427

Automerge-Triggered-By: @pablogsal
(cherry picked from commit 41f0ef6abbd304409c55612a08788cdd59fbc8a3)

Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
3 files changed