Include trace command in Jupyter kernel.

docs/Joy in Jupyter.ipynb

@@ -108,20 +108,36 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 6,
    "id": "f491e33f",
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[1 2 +]"
+     ]
+    }
+   ],
    "source": [
     "[1 2 +]"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 7,
    "id": "31d6ec54",
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "3"
+     ]
+    }
+   ],
    "source": [
     "trace"
    ]

docs/jupyter_kernel/joy_kernel.py

@@ -1,7 +1,11 @@
 from ipykernel.kernelbase import Kernel
-from joy.library import initialize
+from joy.library import initialize, inscribe
 from joy.joy import run
 from joy.utils.stack import stack_to_string
+from joy.utils.pretty_print import trace
+
+
+inscribe(trace)
 
 
 class JoyKernel(Kernel):