Moving Multiple Cells when Dragging

[zachperiscopic]

Selecting multiple cells with the checkbox is super useful, but would be helpful if groups of selected cells could be dragged together. If I select many cells then try to drag them, only the one I click on will move. Same goes for the minimap: being able to command-click multiple cells works well, but am wanting to move my selections as one big chunk. Thanks!

[mootari]

See also https://github.com/observablehq/feedback/issues/398