Update Jest documentation (22.0.4)

Author: Thibaut

lib/docs/filters/jest/clean_html.rb

@@ -18,7 +18,7 @@ def call
         end
 
         css('pre').each do |node|
-          node['data-language'] = node['class'][/language-(\w+)/, 1]
+          node['data-language'] = node['class'][/language-(\w+)/, 1] if node['class']
           node.content = node.content
         end
 

lib/docs/scrapers/jest.rb

@@ -1,7 +1,7 @@
 module Docs
   class Jest < UrlScraper
     self.type = 'jest'
-    self.release = '21.2.1'
+    self.release = '22.0.4'
     self.base_url = 'https://facebook.github.io/jest/docs/en/'
     self.root_path = 'getting-started.html'
     self.links = {