/**
 * @typedef {import('hast').Parent} Parent
 * @typedef {import('hast').Root} Root
 * @typedef {Root|Parent['children'][number]} Node
 */
/**
 * Rank of a heading: H1 -> 1, H2 -> 2, etc.
 *
 * @param {Node} node
 * @returns {number|null}
 */
export function headingRank(node: Node): number | null
export type Parent = import('hast').Parent
export type Root = import('hast').Root
export type Node = Root | Parent['children'][number]