VS Code integrated terminal Intellisense support for `azd`

[JeffreyCA]

There's a new VS Code preview feature that adds Intellisense to the integrated terminal, powered by Fig autocomplete specs:

The default ones bundled with VS Code are located here (looks like some are pulled from upstream withfig/autocomplete): https://github.com/microsoft/vscode/tree/main/extensions/terminal-suggest/src/completions.

Maybe we could contribute a spec for azd upstream?

Relevant:
https://code.visualstudio.com/docs/terminal/shell-integration#_intellisense-preview
https://fig.io/docs/guides/integrating/integrations/cobra