[Doc] Clearer corresponding relationship between configurations for multi-node guides (#3441)

Optimize multi-node guide: more clearer corresponding relationship
between configuration items and nodes

### What this PR does / why we need it?
Some issues caused by misunderstandings due to unclear guidance content,
for example: #3367

### Does this PR introduce _any_ user-facing change?
NA
### How was this patch tested?
NA

- vLLM version: v0.11.0rc3
- vLLM main: https://github.com/vllm-project/vllm/commit/v0.11.0

Signed-off-by: leo-pony <nengjunma@outlook.com>

docs/source/tutorials/multi_node.md

@@ -103,7 +103,7 @@ Before launch the inference server, ensure the following environment variables a
 #!/bin/sh
 
 # this obtained through ifconfig
-# nic_name is the network interface name corresponding to local_ip
+# nic_name is the network interface name corresponding to local_ip of the current node
 nic_name="xxxx"
 local_ip="xxxx"
 
@@ -144,9 +144,14 @@ vllm serve vllm-ascend/DeepSeek-V3.1-W8A8 \
 ```shell
 #!/bin/sh
 
+# this obtained through ifconfig
+# nic_name is the network interface name corresponding to local_ip of the current node
 nic_name="xxx"
 local_ip="xxx"
 
+# The value of node0_ip must be consistent with the value of local_ip set in node0 (master node)
+node0_ip="xxxx"
+
 export VLLM_USE_MODELSCOPE=True
 export HCCL_IF_IP=$local_ip
 export GLOO_SOCKET_IFNAME=$nic_name
@@ -164,7 +169,7 @@ vllm serve vllm-ascend/DeepSeek-V3.1-W8A8 \
 --data-parallel-size 4 \
 --data-parallel-size-local 2 \
 --data-parallel-start-rank 2 \
---data-parallel-address { node0 ip } \
+--data-parallel-address $node0_ip \
 --data-parallel-rpc-port 13389 \
 --tensor-parallel-size 4 \
 --seed 1024 \