Make fixedCollection properties reorderable

I’m working on a particular node that uses a type: 'fixedCollection' multipleValues: true property to specify a list of actions to perform (to wit, it’s a binding for Puppeteer). Quite often, it is necessary to add an entry in the middle of this list or reorder some entries, but as it is right now, new entries can only be added at the bottom (though any entries can be deleted with the “trashcan” icon that appears upon hovering one).

It would be great if the implementation of the parameter editor UI for fixedCollections could be made to let you reorder entries by drag-and-drop (maybe gated behind a typeOptions flag, if this behaviour is presumed undesirable sometimes), or at least insert entries in the middle of the list.