Function prepend

packages/react-stately/src/data/useTreeData.ts:335–337

(parentKey: Key | null, ...values: T[])

      this.insert(parentNode?.key ?? null, index + 1, ...values);
    },
    prepend(parentKey: Key | null, ...values: T[]) {
      this.insert(parentKey, 0, ...values);
    },
    append(parentKey: Key | null, ...values: T[]) {
      if (parentKey == null) {
        this.insert(null, items.length, ...values);