fix: check ``` in hf prefill

Author: terryyz

bigcodebench/provider/vllm.py

@@ -27,7 +27,7 @@ def __init__(self, name: str, dataset: str, tp: int, **kwargs) -> None:
         if self.is_direct_completion():
             self.eos += extra_eos_for_direct_completion(dataset)
         else:
-            if self.prefill:
+            if self.prefill and "```" in self.response_prefix:
                 self.eos += ["\n```\n"]
         self.llm = LLM(model=name, max_model_len=self.max_new_tokens, **kwargs)
         self.llm.set_tokenizer(tokenizer=self.tokenizer)