Fix typo in title (microsoft#1594)

notebook/agentchat_cost_token_tracking.ipynb

@@ -15,7 +15,7 @@
     "\n",
     "Licensed under the MIT License.\n",
     "\n",
-    "# Usage tracking with AtuoGen\n",
+    "# Usage tracking with AutoGen\n",
     "## 1. Use AutoGen's OpenAIWrapper for cost estimation\n",
     "The `OpenAIWrapper` from `autogen` tracks token counts and costs of your API calls. Use the `create()` method to initiate requests and `print_usage_summary()` to retrieve a detailed usage report, including total cost and token usage for both cached and actual requests.\n",
     "\n",