I always get en and em confused. They are all just dashes to me :-).

The "Nothing else: no lists, tables, links, quotes, images or rules" is from the docs indicating that these things are not supported.

I, too, was confused for the longest time, but the secret is in the names.

En dash is the width of an “n”. Em dash is the width of an “M”, so a little wider.

> I always get en and em confused

Yeah, it’s somewhat a typography-nerdy thing :–) (gosh that looks terrible probably; edit: actually it’s surprisingly fine)

> indicating that these things are not supported

Of course, but it does sound a bit unnatural IMO. Then again, I’m going by the vibes here.