fix bug for online chat formatter (#24)

Co-authored-by: wangjian <[email protected]>

lazyllm/components/prompter/builtinPrompt.py

@@ -105,7 +105,7 @@ def _generate_prompt_dict_impl(self, instruction, input, user, history, tools, l
             raise TypeError("input must be a string or a dict")
 
         if user:
-            history[-1]["content"].insert(0, user)
+            history[-1]["content"] = user + history[-1]['content']
 
         history.insert(0, {"role": "system",
                            "content": self._system + "\n" + instruction if instruction else self._system})