Constant jpegxl_sys::JpegxlDataType_JPEGXL_TYPE_BOOLEAN

pub const JpegxlDataType_JPEGXL_TYPE_BOOLEAN: JpegxlDataType = 0;

Use 1-bit packed in uint8_t, first pixel in LSB, padded to uint8_t per row. TODO(lode): support first in MSB, other padding.