Remove all instances of this getSetItems interface and replace it with just setI...

https://api.github.com/acenturyandabit/workflowish/blob/d9dac81df2e15a1b543aaf24406286b3278b7042/src/Workflowish/index.tsx#L158

```javascript

},
disableDelete: () => (itemTree.children.length == 1),
getSetItems: (keys: string[], getSetter: TreeNodesGetSetter) => {
props.transformedDataAndSetter.setItemsByKey((oldData: TransformedData) => {
// TODO: Remove all instances of this getSetItems interface and replace it with just setItemsByKey
const oldItems = keys.map(key => oldData.keyedNodes[key])
const newNodes = getSetter(oldItems);
return newNodes.reduce((nodeDict, node) => {
nodeDict[node.id] = node;
return nodeDict;
}, {} as Record);
});
},
thisItem: itemTree
})}
>)
})}
}

```