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

lib/md044.js

@@ -17,6 +17,7 @@ module.exports = {
   "names": [ "MD044", "proper-names" ],
   "description": "Proper names should have the correct capitalization",
   "tags": [ "spelling" ],
+  "parser": "micromark",
   "function": function MD044(params, onError) {
     let names = params.config.names;
     names = Array.isArray(names) ? names : [];