Update EIP-5679 Add Ref Impl (ethereum#5739)

* init

* Update ERC number

* Add content

* Add discussion-to

* Add ERC-165 identifiers

* Change public to external

* Update with batch and safe methods and add rationale.

* Fix format

* Fix EIPW errors

* Add mentioning of EIP-777

* Add refimpl for Ext20

* Fix

* update

* Update

EIPS/eip-5679.md

@@ -98,6 +98,12 @@ convention of EIP-721 and EIP-1155 respectively.
 
 This EIP is designed to be compatible for EIP-20, EIP-721 and EIP-1155 respectively.
 
+## Reference Implementation
+
+A few reference implementations of this EIP has been deployed onto goerli (ethereum public testnet).
+
+- Interface `IERC5679Ext20` is deployed onto goerli:0x672cf368Bf6c80517B43A83dD06A4041d7eD6C5E, see verified code on etherscan.
+
 ## Security Considerations
 
 This EIP depends on the security soundness of the underlying book keeping behavior of the token implementation.
@@ -109,7 +115,7 @@ The burning should also carefully design the access control. Typically only the
 - Role 1. The current token holder
 - Role 2. An role with special privilege.
 
-Either Role 1 OR Role 2 or a consensus between the two are entitled to conduct the burning action. 
+Either Role 1 OR Role 2 or a consensus between the two are entitled to conduct the burning action.
 However as author of this EIP we do recognize there are potentially other use case where a third type of role shall be entitled
 to burning. We keep this EIP less opinionated in such restriction but implementors should be cautious about designing
 the restriction.