[Doc] ruff format remaining Python examples (#26795)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>

docs/features/quantization/quantized_kvcache.md

@@ -41,9 +41,11 @@ Here is an example of how to enable FP8 quantization:
     from vllm import LLM, SamplingParams
 
     sampling_params = SamplingParams(temperature=0.7, top_p=0.8)
-    llm = LLM(model="meta-llama/Llama-2-7b-chat-hf",
-            kv_cache_dtype="fp8",
-            calculate_kv_scales=True)
+    llm = LLM(
+        model="meta-llama/Llama-2-7b-chat-hf",
+        kv_cache_dtype="fp8",
+        calculate_kv_scales=True,
+    )
     prompt = "London is the capital of"
     out = llm.generate(prompt, sampling_params)[0].outputs[0].text
     print(out)