Curate eos.io links and eosio.contracts folder references

[lparisc]

Change Description

Resolves eosnetworkfoundation/devrel#100 - Curate EOSIO references in antelope reference-contracts Resolves eosnetworkfoundation/devrel#102 - Fix eosio.contracts folder references in reference-contracts

Deployment Changes

• [ ] Deployment Changes

API Changes

• [ ] API Changes

Documentation Additions

• [x] Documentation Additions