* Docs
* Interface definitions
* Fmt and gazelle
* Rename interface to interfaces
* Define all the type for protoarray
* Gaz
* Add error types
* Add compute delta helper
* Compute delta tests
* Gaz
* Add checking if nodes viable
* Test for viable head
* Test for non leaf node can lead to viable head
* Extra space
* Remove fmt print
* Update beacon-chain/forkchoice/protoarray/nodes.go
Co-Authored-By: Nishant Das <nishdas93@gmail.com>
Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>
Co-authored-by: Nishant Das <nish1993@hotmail.com>