Update Step-3.5-Flash vLLM recipe (#2)

- Update Step-3.5-Flash vLLM recipe (e4d3549a39e2ce9c17148846714f5bbf203027fc)


Co-authored-by: jeejeelee <jeeejeee@users.noreply.huggingface.co>

README.md

@@ -211,6 +211,7 @@ vllm serve <MODEL_PATH_OR_HF_ID> \
   --speculative_config '{"method": "step3p5_mtp", "num_speculative_tokens": 1}' \
   --trust-remote-code    
 ```
+You can also refer to the [Step-3.5-Flash](https://github.com/vllm-project/recipes/blob/main/StepFun/Step-3.5-Flash.md) recipe.
 
 ### 6.2 SGLang