Update generate-self-signed-certificates.md (#2703)
Update generate-self-signed-certificates.md (#2703)

* Update generate-self-signed-certificates.md

* Optimize indentation

* Apply suggestions from code review

Co-authored-by: Lilian Lee <c684465c17314189c18707959627e2ec4fdec2d0@pingcap.com>

Co-authored-by: Lilian Lee <c684465c17314189c18707959627e2ec4fdec2d0@pingcap.com>
Co-authored-by: pingcap-github-bot <02289d1d97168591eb26d2551f7cc1b10910d341@pingcap.com>
pingcap/docs,pingcap/docs,pingcap/docs