[Docs] use uv in CPU installation docs (#22089)

Signed-off-by: David Xia <david@davidxia.com>

docs/getting_started/installation/cpu/s390x.inc.md

@@ -1,6 +1,6 @@
 # --8<-- [start:installation]
 
-vLLM has experimental support for s390x architecture on IBM Z platform. For now, users shall build from the vLLM source to natively run on IBM Z platform.
+vLLM has experimental support for s390x architecture on IBM Z platform. For now, users must build from source to natively run on IBM Z platform.
 
 Currently the CPU implementation for s390x architecture supports FP32 datatype only.
 
@@ -40,21 +40,32 @@ curl https://sh.rustup.rs -sSf | sh -s -- -y && \
     . "$HOME/.cargo/env"
 ```
 
-Execute the following commands to build and install vLLM from the source.
+Execute the following commands to build and install vLLM from source.
 
 !!! tip
-    Please build the following dependencies, `torchvision`, `pyarrow` from the source before building vLLM.
+    Please build the following dependencies, `torchvision`, `pyarrow` from source before building vLLM.
 
 ```bash
     sed -i '/^torch/d' requirements-build.txt    # remove torch from requirements-build.txt since we use nightly builds
-    pip install -v \
-        --extra-index-url https://download.pytorch.org/whl/nightly/cpu \
+    uv pip install -v \
+        --torch-backend auto \
         -r requirements-build.txt \
         -r requirements-cpu.txt \
     VLLM_TARGET_DEVICE=cpu python setup.py bdist_wheel && \
-    pip install dist/*.whl
+        uv pip install dist/*.whl
 ```
 
+??? console "pip"
+    ```bash
+        sed -i '/^torch/d' requirements-build.txt    # remove torch from requirements-build.txt since we use nightly builds
+        pip install -v \
+            --extra-index-url https://download.pytorch.org/whl/nightly/cpu \
+            -r requirements-build.txt \
+            -r requirements-cpu.txt \
+        VLLM_TARGET_DEVICE=cpu python setup.py bdist_wheel && \
+            pip install dist/*.whl
+    ```
+
 # --8<-- [end:build-wheel-from-source]
 # --8<-- [start:pre-built-images]
 
@@ -63,19 +74,19 @@ Execute the following commands to build and install vLLM from the source.
 
 ```bash
 docker build -f docker/Dockerfile.s390x \
-        --tag vllm-cpu-env .
+    --tag vllm-cpu-env .
 
-# Launching OpenAI server
+# Launch OpenAI server
 docker run --rm \
-            --privileged=true \
-            --shm-size=4g \
-            -p 8000:8000 \
-            -e VLLM_CPU_KVCACHE_SPACE=<KV cache space> \
-            -e VLLM_CPU_OMP_THREADS_BIND=<CPU cores for inference> \
-            vllm-cpu-env \
-            --model=meta-llama/Llama-3.2-1B-Instruct \
-            --dtype=float \
-            other vLLM OpenAI server arguments
+    --privileged true \
+    --shm-size 4g \
+    -p 8000:8000 \
+    -e VLLM_CPU_KVCACHE_SPACE=<KV cache space> \
+    -e VLLM_CPU_OMP_THREADS_BIND=<CPU cores for inference> \
+    vllm-cpu-env \
+    --model meta-llama/Llama-3.2-1B-Instruct \
+    --dtype float \
+    other vLLM OpenAI server arguments
 ```
 
 # --8<-- [end:build-image-from-source]