function getRightmostColKey({ colgroups, colKeys }) {
    return getLeftmostOrRightmostColKey({
        type: "rightmost",
        colgroups,
        colKeys,
    });
}
@getRightmostColKey
@desc get rightmost column key
@param {array<object>} colgroups
@param {array<any>} colKeys
@return colKey