Add Rule.parser property for custom rules to specify which Markdown parser output they use, honor it strictly, and add full type support.

lib/md026.js

@@ -12,6 +12,7 @@ module.exports = {
   "names": [ "MD026", "no-trailing-punctuation" ],
   "description": "Trailing punctuation in heading",
   "tags": [ "headings" ],
+  "parser": "micromark",
   "function": function MD026(params, onError) {
     let punctuation = params.config.punctuation;
     punctuation = String(