Update Crystal documentation (0.20.3)

lib/docs/filters/crystal/clean_html.rb

@@ -7,7 +7,7 @@ module Docs
       end
 
       def book
-        @doc = at_css('.page-inner > section')
+        @doc = at_css('.page-inner section')
 
         css('pre > code').each do |node|
           node.parent['data-language'] = node['class'][/lang-(\w+)/, 1] if node['class']

lib/docs/scrapers/crystal.rb

@@ -1,7 +1,7 @@
 module Docs
   class Crystal < UrlScraper
     self.type = 'crystal'
-    self.release = '0.20.0'
+    self.release = '0.20.3'
     self.base_url = 'https://crystal-lang.org/'
     self.root_path = "api/#{release}/index.html"
     self.initial_paths = %w(docs/index.html)