[doc] Fold long code blocks to improve readability (#19926)

Signed-off-by: reidliu41 <reid201711@gmail.com>
Co-authored-by: reidliu41 <reid201711@gmail.com>

docs/models/generative_models.md

@@ -85,35 +85,37 @@ and automatically applies the model's [chat template](https://huggingface.co/doc
     In general, only instruction-tuned models have a chat template.
     Base models may perform poorly as they are not trained to respond to the chat conversation.
 
-```python
-from vllm import LLM
+??? Code
 
-llm = LLM(model="meta-llama/Meta-Llama-3-8B-Instruct")
-conversation = [
-    {
-        "role": "system",
-        "content": "You are a helpful assistant"
-    },
-    {
-        "role": "user",
-        "content": "Hello"
-    },
-    {
-        "role": "assistant",
-        "content": "Hello! How can I assist you today?"
-    },
-    {
-        "role": "user",
-        "content": "Write an essay about the importance of higher education.",
-    },
-]
-outputs = llm.chat(conversation)
+    ```python
+    from vllm import LLM
 
-for output in outputs:
-    prompt = output.prompt
-    generated_text = output.outputs[0].text
-    print(f"Prompt: {prompt!r}, Generated text: {generated_text!r}")
-```
+    llm = LLM(model="meta-llama/Meta-Llama-3-8B-Instruct")
+    conversation = [
+        {
+            "role": "system",
+            "content": "You are a helpful assistant"
+        },
+        {
+            "role": "user",
+            "content": "Hello"
+        },
+        {
+            "role": "assistant",
+            "content": "Hello! How can I assist you today?"
+        },
+        {
+            "role": "user",
+            "content": "Write an essay about the importance of higher education.",
+        },
+    ]
+    outputs = llm.chat(conversation)
+
+    for output in outputs:
+        prompt = output.prompt
+        generated_text = output.outputs[0].text
+        print(f"Prompt: {prompt!r}, Generated text: {generated_text!r}")
+    ```
 
 A code example can be found here: <gh-file:examples/offline_inference/basic/chat.py>