Markdown support in broadcast messages

Report https://about.gitlab.com/2016/01/15/making-gitlab-better-for-large-open-source-projects/#comment-2467001042

Nice to be able to add links, some more content than a single line.

Can be annoying if it's too big, though.

@dzaporozhets anything against doing this?

Title changed from markdown support in broardcast messages to Markdown support in broadcast messages

mentioned in issue #12617 (closed)

/cc @DouweM

I think anything with more than one or two line breaks will look really bad -- do we truncate the content ourselves or let people figure that out on their own?

We always say that we don't want people to break their own software. So I'm fine with restricting to 3 lines. Plus the markdown formatting should account for the message and not make massive titles, for instance.

I think limited markdown support would be good. Support links, bold, italics, underline, etc. But not titles, images, lists, etc.

Reassigned to @rspeicher

mentioned in merge request !2693 (merged)

mentioned in merge request !2695 (merged)

mentioned in commit 89b3ddd6

Milestone changed to 8.5

Status changed to closed by merge request !2695 (merged)

Status changed to closed by commit 89b3ddd6

mentioned in commit aacde42d

Which markdown features ended up being supported?

@bbodenmiller Emoji and autolinks, and a limited set of HTML tags (bold, italic, strikethrough, links).