Fix proofs in Script_family.v
Port the file https://nomadic-labs.gitlab.io/coq-tezos-of-ocaml/docs/proto_alpha/proofs/script_family/ to Proto K.
Port the file https://nomadic-labs.gitlab.io/coq-tezos-of-ocaml/docs/proto_alpha/proofs/script_family/ to Proto K.