code: func (fp *formatParser) codeCode(i int, r rune) error {
  	fp.processCode(i)
  	fp.start = i
  	fp.code = (*formatParser).freshCode
  	fp.next = (*formatParser).freshNext
  	fp.end = (*formatParser).freshEnd
  	return nil
  }
docs: // Called when processing a code string and another '%' is found in the format
  // string.