Remove bad reference to Pro model. (google-gemini#264)

This example uses the Flash model, but the intro text says Pro.

quickstarts/Video.ipynb

@@ -59,7 +59,7 @@
         "id": "q7QvXQMrIhuZ"
       },
       "source": [
-        "This notebook provides a quick example of how to prompt Gemini 1.5 Pro using a video file. In this case, you'll use a short clip of [Big Buck Bunny](https://peach.blender.org/about/)."
+        "This notebook provides a quick example of how to prompt the Gemini API using a video file. In this case, you'll use a short clip of [Big Buck Bunny](https://peach.blender.org/about/)."
       ]
     },
     {