code: func (p *printer) heredocIndent(buf []byte) []byte {
  	var res []byte
  	bol := false
  	for _, c := range buf {
  		if bol && c != '\n' {
  			res = append(res, unindent...)
  		}
  		res = append(res, c)
  		bol = c == '\n'
  	}
  	return res
  }
docs: // heredocIndent marks all the 2nd and further lines as unindentable