Add docs nav entry for .gitlab-ci.yml introduction (!4357) · Merge requests · GitLab.org / GitLab Docs DEPRECATED · GitLab

Add navigation item to global navigation

~~Link to the merge request that introduced the new page:~~
Give the MR a descriptive title.
Optional. Link to the review app showing the new page: https://docs.gitlab.com/ee/ci/yaml/gitlab_ci_yaml.html

Parent issue: #1722 (closed)