Remove gitlab-markup custom patches
We no longer need to patch gitlab-markup as we've added the required changes natively to the gem.
Check: gitlab-markup!9 (merged) for details.
This merge request depends on https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/26246 getting merged first.
Part of https://gitlab.com/gitlab-org/gitlab-ce/issues/59062
Edited by GitLab Release Tools Bot