    # File lib/yard/templates/helpers/markup_helper.rb, line 122
          def markup_for_file(contents, filename)
            if contents && contents =~ MARKUP_FILE_SHEBANG # Shebang support
              return $1.to_sym
            end

            ext = (File.extname(filename)[1..-1] || '').downcase
            MARKUP_EXTENSIONS.each do |type, exts|
              return type if exts.include?(ext)
            end
            options.markup
          end