doc: Remove -whitelistforcerelay from comment
doc: Remove -whitelistforcerelay from comment

Instead, permission flags should be used. For example
-whitelist=forcerelay@127.0.0.1


Former-commit-id: 13b83058eabf2aeea9ba4d8539d593d66da11828
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin