code: func AdjustBrightness(img image.Image, percentage float64) *image.NRGBA {
  	percentage = math.Min(math.Max(percentage, -100.0), 100.0)
  	lut := make([]uint8, 256)
  
  	shift := 255.0 * percentage / 100.0
  	for i := 0; i < 256; i++ {
  		lut[i] = clamp(float64(i) + shift)
  	}
  
  	return adjustLUT(img, lut)
  }
docs: // AdjustBrightness changes the brightness of the image using the percentage parameter and returns the adjusted image.
  // The percentage must be in range (-100, 100). The percentage = 0 gives the original image.
  // The percentage = -100 gives solid black image. The percentage = 100 gives solid white image.
  //
  // Examples:
  //
  //	dstImage = imaging.AdjustBrightness(srcImage, -15) // Decrease image brightness by 15%.
  //	dstImage = imaging.AdjustBrightness(srcImage, 10) // Increase image brightness by 10%.
  //