Autolink enum cases

[reitzig]

Say I have something like this:

/**
	Use `.bar` if you are a pirate, `.spa` if you are a landlubber.
*/
enum Foo {
	case bar, spa
}

I would expect the enum cases in the documentation comment to link to the respective cases, but they currently don't.

[johnfairh]

This is the same as #865. The name of enum element is just bar and needs to be referred to as `Foo.bar` from that position.