cmd/api needs to be updated for generics. For example, this is what it currently outputs for the constraints package:

pkg constraints, type Chan interface {}
pkg constraints, type Complex interface {}
pkg constraints, type Float interface {}
pkg constraints, type Integer interface {}
pkg constraints, type Map interface {}
pkg constraints, type Ordered interface {}
pkg constraints, type Signed interface {}
pkg constraints, type Slice interface {}
pkg constraints, type Unsigned interface {}

It also looks like it could panic on a generic type declaration. I don't think this will be particularly tricky, but it is a release-blocker.

I am happy to make this change, though if anyone else wants to take it this would be a good opportunity to use the new go/ast and go/types APIs.