Update Electron documentation (20.0.0)

lib/docs/filters/electron/clean_html.rb

@@ -12,6 +12,11 @@ module Docs
 
         css("footer").remove
 
+        css('pre').each do |node|
+          node.content = node.css('.token-line').map(&:content).join("\n")
+          node['data-language'] = 'javascript'
+        end
+
         doc
       end
     end