merge !1001

document image link=self attribute introduced by #735 (closed)

(cherry picked from commit 18016b28)

05111766 Document image link=self attribute

I encountered a problem with GitLab Pages deployment. It prevented me from deploying new projects on several different subdomains for many weeks. I troubleshooted it with my DevOPS support team; it was breaking our certificate's chain of trust. We were stumped; somehow in the last nine months we performed an upgrade. All new projects failed to deploy correctly, even new ones in the same subgroup where working with established repositories. I thought there was something wrong with our self-signed certificate, GitLab CLI configuration, or that our corporate network was rewriting the URL.

I came to document the issue in the GitLab Pages information. I found one mention of this after the fact in the Antora Zulipchat. https://antora.zulipchat.com/#narrow/stream/282400-users/topic/.E2.9C.94.20Publish.20to.20GitHub.20pages

The HTTP 308 error issue is described at https://forum.gitlab.com/t/gitlab-pages-with-custom-domain-redirects-back-to-gitlab-subdomain/93113