feat: validate illformed YAML comments (#180)

Refs: nodejs/node#38324

Author: aduh95

remark-lint-nodejs-yaml-comments.js

@@ -219,6 +219,11 @@ function validateMeta(node, file, meta) {
 
 function validateYAMLComments(tree, file) {
  visit(tree, "html", function visitor(node) {
+ if (node.value.startsWith("<!--YAML\n"))
+ file.message(
+ "Expected `<!-- YAML`, found `<!--YAML`. Please add a space",
+ node
+ );
  if (!node.value.startsWith("<!-- YAML\n")) return;
  try {
  const meta = yaml.load("#" + node.value.slice(0, -"-->".length));