Update ERCS/erc-7969.md

Co-authored-by: Ernesto García <[email protected]>

Author: 0xknon

ERCS/erc-7969.md

@@ -57,7 +57,7 @@ interface IDKIMRegistry {
 
 The `domainHash` parameter MUST be the hash of the lowercase domain name or subdomain name. For example:
 
-- For the domain "example.com":
+- For the domain "example.com" using keccak256:
 
 ```solidity
 domainHash = keccak256(bytes("example.com"))