Index of Y.Array in forEach method starts from 1

[stellit]

Describe the bug
Index of Y.Array in forEach start from 1
It seems that the issue only affect 14.0.0-0

To Reproduce

test('yarray-index-test', () => {
    const doc = new Y.Doc();
    const yArr = doc.getArray('');
    yArr.push(['elem 1', 'elem 2']);
    yArr.forEach((elem, index, arr) => {
        console.log(`index: ${index}`); // starts from 1
        arr.get(index); // error will be thrown when get the last element with index.
    });
});

It seems that the index got increased by this line: https://github.com/yjs/yjs/blob/v14.0.0-0/src/utils/ListCursor.js#L313

Expected behavior
index in the forEach should starts from 0,

Environment Information

• Yjs version: v14.0.0-0