docs: add transforms in OxfordIIITPet. (fix #8812 )

Author: GdoongMathew

torchvision/datasets/oxford_iiit_pet.py

@@ -27,6 +27,8 @@ class OxfordIIITPet(VisionDataset):
  transform (callable, optional): A function/transform that takes in a PIL image and returns a transformed
  version. E.g, ``transforms.RandomCrop``.
  target_transform (callable, optional): A function/transform that takes in the target and transforms it.
+ transforms (callable, optional): A function/transform that takes input sample
+ and its target as entry and returns a transformed version.
  download (bool, optional): If True, downloads the dataset from the internet and puts it into
  ``root/oxford-iiit-pet``. If dataset is already downloaded, it is not downloaded again.
  """