Link to markdown help is broken
In editable cell, the link to the markdown help points to this page which only contains:
This document was moved to user/markdown.md.
I guess it's easy to fix this redirection.
Tested on gitlab.com (GitLab Enterprise Edition 8.11.0-ee e249da43) and our own gitlab instance (GitLab Community Edition 8.11.0 346e677e) (8.11.1 and 8.11.2 do not seem to correct that according to the changelog