rename JSON field 'hashcash' to 'pow_token' in API request body

README.md

@@ -994,7 +994,7 @@ difficulty is advertised via `GET /api/v1/server` in the `hashcash_bits` field.
 
 **Request Body:**
 ```json
-{"nick": "alice", "hashcash": "1:20:260310:neoirc::3a2f1"}
+{"nick": "alice", "pow_token": "1:20:260310:neoirc::3a2f1"}
 ```
 
 | Field      | Type   | Required    | Constraints |
@@ -1030,7 +1030,7 @@ difficulty is advertised via `GET /api/v1/server` in the `hashcash_bits` field.
 ```bash
 TOKEN=$(curl -s -X POST http://localhost:8080/api/v1/session \
   -H 'Content-Type: application/json' \
-  -d '{"nick":"alice","hashcash":"1:20:260310:neoirc::3a2f1"}' | jq -r .token)
+  -d '{"nick":"alice","pow_token":"1:20:260310:neoirc::3a2f1"}' | jq -r .token)
 echo $TOKEN
 ```