fix comment

nnunetv2/imageio/natural_image_reader_writer.py

@@ -43,7 +43,7 @@ def read_images(self, image_fnames: Union[List[str], Tuple[str, ...]]) -> Tuple[
                 assert npy_img.shape[-1] == 3 or npy_img.shape[-1] == 4, "If image has three dimensions then the last " \
                                                                          "dimension must have shape 3 or 4 " \
                                                                          f"(RGB or RGBA). Image shape here is {npy_img.shape}"
-                # move RGB(A) to front, add additional dim so that we have shape (1, c, X, Y), where c is either 3 or 4
+                # move RGB(A) to front, add additional dim so that we have shape (c, 1, X, Y), where c is either 3 or 4
                 images.append(npy_img.transpose((2, 0, 1))[:, None])
             elif npy_img.ndim == 2:
                 # grayscale image