Fix custom renderer with unsafe option missing pre lang

Author: kazk

lib/html/pipeline/markdown_filter.rb

@@ -38,7 +38,7 @@ def call
 
           render_options = [:GITHUB_PRE_LANG]
           render_options << :HARDBREAKS if context[:gfm] != false
-          render_options = [:UNSAFE] if context[:unsafe]
+          render_options << :UNSAFE if context[:unsafe]
 
           doc = CommonMarker.render_doc(@text, parse_options, extensions)
           renderer.new(options: render_options, extensions: extensions).render(doc)

test/html/pipeline/markdown_filter_test.rb

@@ -119,6 +119,11 @@ def test_legitimate_custom_renderer_without_tagfilter
 
     assert_equal results, script
   end
+
+  def test_unsafe_custom_renderer_fenced_code_blocks_with_language
+    doc = MarkdownFilter.to_document(@code.sub('```', '``` ruby'), unsafe: true, commonmarker_renderer: CustomRenderer)
+    assert_equal 'ruby', doc.search('pre').first['lang']
+  end
 end
 
 class GFMTest < Minitest::Test