Docs: Libp2p Interface code reference broken in libp2p core package

The code path that links to where the libp2p interface as defined in the [libp2p index](https://github.com/libp2p/js-libp2p/blob/master/packages/libp2p/src/index.ts#L44) is currently broken as can be observed on the [generated doc](https://libp2p.github.io/js-libp2p/interfaces/libp2p.index.Libp2p.html)