Windows Sandbox docs aren't up-to-date

Question

### What is the type of issue?

Documentation is missing

### What is the issue?

A recent PR #11341 and it's following release promoted windows sandbox out of experimental, but the documentation hasn't been updated. On there, the feature is still marked as experimental and missing latest changes. There are no up-to-date examples on how to use this feature (for example `windows.sandbox` config values and what they do or the `/setup-default-sandbox` slash command).

### Where did you find it?

ht