Jekyll monkeypatch to strip leading space from indented `highlight` liquid blocks

highlight_indent_fix.rb

Jekyll::Tags::HighlightBlock.module_eval do

  def render(context)
    code = strip_leading_space_from super
    if context.registers[:site].pygments
      render_pygments(context, code)
    else
      render_codehighlighter(context, code)
    end
  end

  def strip_leading_space_from(code)
    leading = code.split("\n").map { |l| /^(\s*)/.match(l)[1].size }
    leading.shift # first line is blank, always (liquid?)
    if leading.min > 0
      code = code.split("\n").map do |line|
        line.sub!(/^\s{#{leading.min}}/, "")
      end.join("\n")
    end
    code
  end

end