fix: update markdown-it to v14.1.0

This allows to use the same version as markdownlint v0.34.0.

src/index.js

@@ -22,6 +22,7 @@ const customRule = {
   names: ["relative-links"],
   description: "Relative links should be valid",
   tags: ["links"],
+  parser: "markdownit",
   function: (params, onError) => {
     filterTokens(params, "inline", (token) => {
       const children = token.children ?? []

src/markdownlint-rule-helpers/helpers.js

@@ -15,7 +15,7 @@
  * @returns {void}
  */
 const filterTokens = (params, type, handler) => {
-  for (const token of params.tokens) {
+  for (const token of params.parsers.markdownit.tokens) {
     if (token.type === type) {
       handler(token)
     }