Convert types.d.mts from ambient module declaration to module augment…

…ation which enables VS Code to handle `@type {import("markdownlint").Rule}` (https://www.typescriptlang.org/docs/handbook/modules/reference.html#ambient-modules), fix broken markdownlint @typedefs in helpers/*.cjs.

helpers/helpers.cjs

@@ -10,11 +10,11 @@ module.exports.newLineRe = newLineRe;
 module.exports.nextLinesRe = nextLinesRe;
 
 // @ts-expect-error https://github.com/microsoft/TypeScript/issues/52529
-/** @typedef {import("markdownlint").RuleOnError} RuleOnError */
+/** @typedef {import("../lib/exports.mjs").RuleOnError} RuleOnError */
 // @ts-expect-error https://github.com/microsoft/TypeScript/issues/52529
-/** @typedef {import("markdownlint").RuleOnErrorFixInfo} RuleOnErrorFixInfo */
+/** @typedef {import("../lib/exports.mjs").RuleOnErrorFixInfo} RuleOnErrorFixInfo */
 // @ts-expect-error https://github.com/microsoft/TypeScript/issues/52529
-/** @typedef {import("markdownlint").MicromarkToken} MicromarkToken */
+/** @typedef {import("../lib/exports.mjs").MicromarkToken} MicromarkToken */
 // eslint-disable-next-line jsdoc/valid-types
 /** @typedef {import("micromark-extension-gfm-footnote", { with: { "resolution-mode": "import" } })} */
 // eslint-disable-next-line jsdoc/valid-types

helpers/micromark-helpers.cjs

@@ -7,7 +7,7 @@ const { flatTokensSymbol, htmlFlowSymbol } = require("./shared.cjs");
 // eslint-disable-next-line jsdoc/valid-types
 /** @typedef {import("micromark-util-types", { with: { "resolution-mode": "import" } }).TokenType} TokenType */
 // @ts-expect-error https://github.com/microsoft/TypeScript/issues/52529
-/** @typedef {import("markdownlint").MicromarkToken} Token */
+/** @typedef {import("../lib/exports.mjs").MicromarkToken} Token */
 
 /**
  * Determines if a Micromark token is within an htmlFlow type.

lib/types.d.mts

@@ -1,3 +1,4 @@
+export {};
 declare module "markdownlint" {
   export * from "./exports.mjs";
 }