def breakdown_by_file
      @file_breakdown ||= begin
        breakdown = Hash.new { |h,k| h[k] = Array.new }
        cache.each do |filename, (language, _)|
          breakdown[language] << filename.dup.force_encoding("UTF-8").scrub
        end
        breakdown
      end
    end
def breakdown_by_file
      @file_breakdown ||= begin
        breakdown = Hash.new { |h,k| h[k] = Array.new }
        cache.each do |filename, (language, _)|
          breakdown[language] << filename.dup.force_encoding("UTF-8").scrub
        end
        breakdown
      end
    end
Public: Return the language breakdown of this repository by file

 Returns a map of language names => [filenames...]