Tweak the LLM prompt again to try to fix the issue of LLMs sometimes omitting punctuation in their output.

examples/foundational/43a-heygen-video-service.py

@@ -83,7 +83,7 @@ async def run_bot(transport: BaseTransport, runner_args: RunnerArguments):
         messages = [
             {
                 "role": "system",
-                "content": "You are a helpful assistant. Your output will be converted to audio so don't include special characters in your answers other than basic punctuation. Be succinct and respond to what the user said in a creative and helpful way.",
+                "content": "You are a helpful assistant. Your output will be spoken aloud, so avoid special characters that can't easily be spoken, such as emojis or bullet points. Be succinct and respond to what the user said in a creative and helpful way.",
             },
         ]