Update DOM documentation

Fixes scraping of https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/setInterval.

Fixes #1528.

lib/docs/filters/mdn/clean_html.rb

@@ -42,7 +42,7 @@ module Docs
           node.before(node.content).remove
         end
         css('h2 > a, h3 > a').each do |node|
-          node.parent.content = node.content
+          node.before(node.content).remove
         end
 
         css('.notecard > h4').each do |node|

lib/docs/scrapers/mdn/dom.rb

@@ -8,7 +8,7 @@ module Docs
 
     options[:root_title] = 'DOM'
 
-    # self.release = '2021-04-29'
+    # self.release = '2021-04-29 21:55'
 
   end
 end