example node alias fix for issue f9f4b61 — radicle.xyz

Replace example node alias with a self-describing one that is more clear for first time readers.

 consists of an Ed25519 key pair and directory under which Radicle stores user
 data.
     rad auth --alias seed.mentharos.net
     rad auth --alias seed.example.com
 The above command will create a profile with the given node *alias* in
 `~/.radicle`, or `$RAD_HOME` if set. We recommend setting your alias to the

 Second, we must set an external address for the node to be reached on the
 network. This address will be advertised to peers, allowing them to connect to
 your seed node. Generally, this will be a DNS name with port `8776`, for
 example `seed.mentharos.net:8776`.
 example `seed.example.com:8776`.
 Here's an example minimal configuration file with a permissive seeding policy
 and external address set:

 ```json
 {
   "node": {
     "alias": "seed.mentharos.net",
     "externalAddresses": ["seed.mentharos.net:8776"],
     "alias": "seed.example.com",
     "externalAddresses": ["seed.example.com:8776"],
     "policy": "allow",
     "scope": "all"
   }

 You'll find this setting in your configuration file, under
 `node.externalAddresses`. External addresses are JSON strings of the form
 `<host>:<port>`, for example `seed.mentharos.net:8776`, where `<host>` is a
 `<host>:<port>`, for example `seed.example.com:8776`, where `<host>` is a
 DNS name, and port is usually `8776`.
 ```json
 {
   "node": {
     ...
     "externalAddresses": ["seed.mentharos.net:8776"]
     "externalAddresses": ["seed.example.com:8776"]
   }
 }
 ```