Users see:
Type here. Use Markdown, BBCode, or HTML to format.
OK, they use Markdown, BBCode, or HTML, but find some things don’t work,
and there are other things other users use that work but they didn’t
know about.
So there are different versions of Markdown, BBCode, or HTML.
So in Help, Discourse should say what versions.
Or instead of that, simply have the full list of markup items that
Discourse uses.
Or at least have a link to where in the source code it is.
But normal users couldn’t understand that source code,
So it still would be better to have a full list, or call it cheatsheat,
of Discourse implemented markup operators.