[whatwg] WA1: content models of i and dfn

[fantasai]

fantasai wrote:
> <dfn> excludes <dfn>. Would it make sense for it to also exclude <i>?
> And should <i> exclude <i> and/or <dfn>, too?
> And shouldn't they both require significant inline content?

Responding to myself.. I think <i> excluding <dfn> would make sense,
but not the other way around, and <i> should not exclude <i>, but
both should require significant inline content.

~fantasai