Update TypeScript Advanced Services Guide

[grant]

Expected Behavior

Developers can get autocompletion with Advanced Services.

Actual Behavior

No autocompletion.

Steps to Reproduce the Problem

1. Install @types/google-apps-script

Wait until this PR is merged:
DefinitelyTyped/DefinitelyTyped#34212

[grant]

That PR is merged.

Need to update the guide.
It may involve modifying the user symbol for the advanced service for autocompletion to work best. (Slides_v1 vs Slides)

[grant]

Also document Apps Script Event types which I added recently:

type SheetsOnOpen = GoogleAppsScript.Events.SheetsOnOpen;

function onOpen(e: SheetsOnOpen) {
  console.log(e.triggerUid);
}