Fix markdown

https://gitlab.com/help/markdown/markdown.md cc @dzaporozhets

@skyruler A while back I played around with making a special case for this page where we showed the raw Markdown on the left half of the screen and the rendered HTML on the right. Let me know if you want to work on something like that.

@rspeicher for now it's styling but I like your idea!

@skyruler Ok.

There's a cool feature of the Markdown processing we're not using that generates a table of contents ol element based on the headers in the document. It'd be awesome if we could implement that into the design of all of the help pages somehow.

@rspeicher I dont understand that. Can you explain?

@skyruler 8.0 is released. What is the status of this?

ping @rspeicher

@job you can close it or check the dev server

Thanks

Status changed to closed

mentioned in merge request !14785