fix typo

gemini/use-cases/retrieval-augmented-generation/rag_pipeline_terabyte_scale_with_bigframes.ipynb

@@ -202,7 +202,7 @@
         "id": "dmWOrTJ3gx13"
       },
       "source": [
-        "### Authenticate your notebook environment (Colab only)\n",
+        "## Authenticate your notebook environment (Colab only)\n",
         "\n",
         "If you're running this notebook on Google Colab, run the cell below to authenticate your environment."
       ]
@@ -229,7 +229,7 @@
         "id": "DF4l8DTdWgPY"
       },
       "source": [
-        "### Set Google Cloud project information and initialize Vertex AI SDK\n",
+        "## Set Google Cloud project information and initialize Vertex AI SDK\n",
         "\n",
         "To get started using Vertex AI, you must have an existing Google Cloud project and [enable the Vertex AI API](https://console.cloud.google.com/flows/enableapi?apiid=aiplatform.googleapis.com).\n",
         "\n",