doc(user): improve "How to deploy a permanent rpc node"

docs/user/rpc.md

@@ -10,7 +10,7 @@
 - In the same folder, create a `.env` file that defime environment variables `SERVER_DOMAIN` and `PEER_ID`:
 ```
 SERVER_DOMAIN=YOUR_DOMAIN
-PEER_ID=Your node peer id
+PEER_ID=YOUR_PEER_ID
 ```
 
 Your `PEER_ID` shoud be generated with this command: `docker run --rm -it --entrypoint duniter -v $PWD:/var/lib/duniter/  duniter/duniter-v2s:v0.1.0 key generate-node-key --file /var/lib/duniter/node.key`