Merge branch '262674-ci-add-retry-exit-code-documentation' into 'master'

Add retry:exit_codes documentation and CI schema

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/137348



Merged-by: Jose Ivan Vargas <jvargas@gitlab.com>
Approved-by: Michael Becker <11881043-wandering_person@users.noreply.gitlab.com>
Approved-by: Lysanne Pinto <lpinto@gitlab.com>
Approved-by: Sascha Eggenberger <seggenberger@gitlab.com>
Approved-by: Robert Hunt <rhunt@gitlab.com>
Approved-by: Jose Ivan Vargas <jvargas@gitlab.com>
Reviewed-by: Michael Becker <11881043-wandering_person@users.noreply.gitlab.com>
Co-authored-by: Baptiste Lalanne <baptiste.lalanne@outlook.fr>