new response to invalidated question (#21)

cfg.py

@@ -47,7 +47,7 @@ buster_cfg = BusterConfig(
         "unknown_threshold": 0.85,
         "embedding_model": "text-embedding-ada-002",
         "use_reranking": True,
-        "invalid_question_response": "This question does not seem relevant to my current knowledge.",
+        "invalid_question_response": "This question does not seem relevant my AI knowledge. If the question is related to AI, please send us feedback! \n PS: I'm still learning, so I might not know the answer to your question, you can also try without acronyms in your question.",
         "check_question_prompt": """You are a chatbot, answering questions about large language models and artificial intelligence.
 Your job is to determine whether user's question is valid or not. Users will not always submit a question either.
 Users will ask all sorts of questions, and some might be tangentially related to artificial intelligence.