add generative AI reminder in lecture 4

Author: afeld

lecture_4.ipynb

@@ -16,6 +16,19 @@
     "_Please sign attendance sheet; close devices_\n"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "source": [
+    "## Generative AI\n",
+    "\n",
+    "Reminder about the [course policy](https://python-public-policy.afeld.me/en/{{school_slug}}/syllabus.html#academic-integrity).\n"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {