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, 3 insertions, 3 deletions

diff --git a/cli/tools/jupyter/server.rs b/cli/tools/jupyter/server.rs
index 391d202fd..2c7bea9d2 100644
--- a/cli/tools/jupyter/server.rs
+++ b/cli/tools/jupyter/server.rs
@@ -551,13 +551,13 @@ async fn get_jupyter_display(
     .post_message_with_event_loop(
       "Runtime.callFunctionOn",
       Some(json!({
-        "functionDeclaration": r#"function (object) {
+        "functionDeclaration": r#"async function (object) {
       if (typeof object[Symbol.for("Jupyter.display")] !== "function") {
         return null;
       }
-      
+
       try {
-        const representation = object[Symbol.for("Jupyter.display")]();
+        const representation = await object[Symbol.for("Jupyter.display")]();
         return JSON.stringify(representation);
       } catch {
         return null;