Update Express documentation (4.21.2)

lib/docs/filters/express/clean_html.rb

@@ -3,7 +3,7 @@ module Docs
     class CleanHtmlFilter < Filter
       def call
         i = 1
-        n = at_css("#navmenu a[href='#{result[:path].split('/').last}']").parent
+        n = at_css("#navmenu .submenu-content a[href='#{result[:path].split('/').last}']").parent
         i += 1 while n && n = n.previous_element
         at_css('h1')['data-level'] = i
 

lib/docs/scrapers/express.rb

@@ -2,7 +2,7 @@ module Docs
   class Express < UrlScraper
     self.name = 'Express'
     self.type = 'express'
-    self.release = '4.18.1'
+    self.release = '4.21.2'
     self.base_url = 'https://expressjs.com/en/'
     self.root_path = '4x/api.html'
     self.initial_paths = %w(