Test quick pick enhancements

[jrieken]

• any os @bpasero

We have improved the quick pick API to allow for a second row with details and to be pinged when an item is selected/focused. Ensure that

• the API is easy to understand
• you can have octicons in the label, description, and detail ($(check) this)
• you can provide a onDidSelectItem function which is called when selecting items in the list
• give feedback if onDidSelectItem is the proper name to use

[egamma]

Suggest to add test sample for this test case to the vscode-samples project.