docs: private void encode(long bits, StringBuilder sb) {
          if (bits < 0) {
              sb.append(characters[(int) ((bits % base + base) % base)]);
  
              bits /= -base;
          }
  
          while (bits > 0) {
              sb.append(characters[(int) (bits % base)]);
  
              bits /= base;
          }
      }