kitti docs (#4251)

Co-authored-by: Francisco Massa <fvsmassa@gmail.com>

torchvision/datasets/kitti.py

@@ -9,7 +9,9 @@ from .vision import VisionDataset
 
 
 class Kitti(VisionDataset):
-    """`KITTI <http://www.cvlibs.net/datasets/kitti>`_ Dataset.
+    """`KITTI <http://www.cvlibs.net/datasets/kitti/eval_object.php?obj_benchmark>`_ Dataset.
+
+    It corresponds to the "left color images of object" dataset, for object detection.
 
     Args:
         root (string): Root directory where images are downloaded to.