701: Fix cargo doc warnings due to unresolved links r=kvark a=manugildev This PR fixes 13 warnings caused by unresolved internal and external(wgt) links in `cargo doc`. > <img width="800" alt="Screenshot 2021-01-06 at 18 33 00" src="https://user-images.githubusercontent.com/13288771/103807298-809b4100-5056-11eb-8667-752f4bdd7902.png"> Co-authored-by: Manuel Gil <manugildev@gmail.com>