Fix rails clean_html_guides filter

lib/docs/filters/rails/clean_html_guides.rb

@@ -24,7 +24,9 @@ module Docs
 
         css('pre').each do |node|
           code = node.at_css('code')
-          language = code['class'][/highlight ?(\w+)/, 1]
+          language = code['class']
+          break if language.nil?
+          language = language [/highlight ?(\w+)/, 1]
           node['data-language'] = language unless language == 'plain'
           code.remove_attribute('class')
           node.content = node.content.strip

lib/docs/scrapers/rdoc/rails.rb

@@ -109,7 +109,6 @@ module Docs
 
     def get_latest_version(opts)
       doc = fetch_doc('https://rubyonrails.org/', opts)
-      doc
       doc.at_css('.heading__button span').content.scan(/\d\.\d*\.*\d*\.*\d*/)[0]
     end
   end