feat(unstable): Await return from `Jupyter.display` (#20807)

Allows `Jupyter.display` to return a promise.

Example:

```javascript
class WikiPage {
    constructor(public name) {}
    async [Symbol.for("Jupyter.display")]() {
        let response = await fetch("https://en.wikipedia.org/wiki/" + this.name);
        return { "text/html": await response.text() }
    }
}

new WikiPage("Deno_(software)")
```

1 files changed, 37 insertions, 0 deletions

diff --git a/cli/tests/testdata/jupyter/integration_test.ipynb b/cli/tests/testdata/jupyter/integration_test.ipynb
index 25d55e88c..b8aed651c 100644
--- a/cli/tests/testdata/jupyter/integration_test.ipynb
+++ b/cli/tests/testdata/jupyter/integration_test.ipynb
@@ -827,6 +827,43 @@
     "let sc = new SuperColor()\n",
     "sc"
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 27,
+   "id": "c1296291-a3e8-457b-8329-6cc58a1e528a",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<div style=\"width: 32px; height: 32px; background-color: #239814\" />"
+      ]
+     },
+     "execution_count": 27,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "class SuperColorAsync {\n",
+    "  constructor() {\n",
+    "      this.color = \"#239814\"\n",
+    "  }\n",
+    "  hex() {\n",
+    "      return this.color\n",
+    "  }\n",
+    "    \n",
+    "  async [Symbol.for(\"Jupyter.display\")]() {\n",
+    "      return {\n",
+    "          \"text/html\": `<div style=\"width: 32px; height: 32px; background-color: ${this.hex()}\" />`\n",
+    "      }\n",
+    "  }\n",
+    "}\n",
+    "\n",
+    "let sc = new SuperColorAsync()\n",
+    "sc"
+   ]
   }
  ],
  "metadata": {