message: doc: Add missing subcommand `run` in README
diff: @@ -125,8 +125,8 @@ curl -d '{"id": 2, "jsonrpc": "2.0", "method":"send_transaction","params": [{"ve
  Run multiple nodes in different `data-dir`:
  ```shell
  -target/release/ckb --data-dir=/tmp/node1
  -target/release/ckb --data-dir=/tmp/node2
  +target/release/ckb run --data-dir=/tmp/node1
  +target/release/ckb run --data-dir=/tmp/node2
  ```
  The file `config.json` in `data-dir` overrides default configurations. Start with the default one:
  