function _createAlignedIns(depth) {
        return DOM.ins({
            className: "jstree-icon",
            style: {
                marginLeft: INDENTATION_WIDTH * depth
            }
        });
    }
@private

Create, and indent correctly, the arrow icons used for the folders.

@param {int} depth The depth of the current node.
@return {PreactComponent} The resulting ins.