Fix docs generator

package.json

@@ -19,7 +19,7 @@
     "test": "npm run lint && c8 mocha && node support/specsplit.mjs",
     "coverage": "npm run test && c8 report --reporter html",
     "report-coveralls": "c8 --reporter=lcov mocha",
-    "doc": "node support/build_doc.js",
+    "doc": "node support/build_doc.mjs",
     "gh-doc": "npm run doc && gh-pages -d apidoc -f",
     "demo": "npm run lint && node support/build_demo.js",
     "gh-demo": "npm run demo && gh-pages -d demo -f -b master -r git@github.com:markdown-it/markdown-it.github.io.git",

support/build_doc.js → support/build_doc.mjs

@@ -1,10 +1,6 @@
 #!/usr/bin/env node
 
-'use strict';
-
-/* eslint-env es6 */
-
-const shell = require('shelljs');
+import shell from 'shelljs';
 
 shell.rm('-rf', 'apidoc');
 
@@ -12,4 +8,4 @@ const head = shell.exec('git show-ref --hash HEAD').stdout.slice(0, 6);
 
 const link_format = `https://github.com/{package.repository}/blob/${head}/{file}#L{line}`;
 
-shell.exec(`node node_modules/.bin/ndoc --link-format "${link_format}"`);
+shell.exec(`node node_modules/.bin/ndoc --alias mjs:js --link-format "${link_format}"`);