Shoutout/Intro for Pester Test Adapter for VSCode

[fflaten]

Checklist

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Summary of the request

Should update https://pester.dev/docs/usage/vscode with a section for the official VSCode (preview-)extension for Pester, https://github.com/pester/vscode-adapter

Suggested section

Usage

[fflaten]

What do you think @JustinGrote ? Just mention it with a link to the marketplace and a bulleted list of notable features they should check out? 🙂

[JustinGrote]

It's still kind of unstable so as long as it's clear it's still in preview I'm OK with it.