'code_block' closer to original implementation

- utilize the 'out' method to output the 'fence_info',
  which converts to utf8
- output 'sourcepos' again

lib/banzai/renderer/common_mark/html.rb

@@ -4,15 +4,11 @@ module Banzai
       class HTML < CommonMarker::HtmlRenderer
         def code_block(node)
           block do
-            code      = node.string_content
-            lang      = node.fence_info
-            lang_attr = lang.present? ? %Q{ lang="#{lang}"} : ''
-            result    =
-              "<pre>" \
-                "<code#{lang_attr}>#{ERB::Util.html_escape(code)}</code>" \
-              "</pre>"
-
-            out(result)
+            out("<pre#{sourcepos(node)}><code")
+            out(' lang="', node.fence_info, '"') if node.fence_info.present?
+            out('>')
+            out(escape_html(node.string_content))
+            out('</code></pre>')
           end
         end
       end

spec/lib/banzai/filter/markdown_filter_spec.rb

@@ -40,6 +40,12 @@ describe Banzai::Filter::MarkdownFilter do
 
         expect(result).to start_with("<pre><code>")
       end
+
+      it 'works with utf8 chars in language' do
+        result = filter("```日\nsome code\n```")
+
+        expect(result).to start_with("<pre><code lang=\"日\">")
+      end
     end
 
     context 'using Redcarpet' do