Docs: update links guideline to inline links
See the general Documentation guidelines http://docs.gitlab.com/ce/development/doc_styleguide.html
What does this MR do?
Port from CE: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/13677
See the general Documentation guidelines http://docs.gitlab.com/ce/development/doc_styleguide.html
Port from CE: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/13677