[fbsync] Docs: update pycocotools url in CocoDetection and CocoCaptions. (#8932)

Reviewed By: scotts

Differential Revision: D77997058

fbshipit-source-id: 7bc12f2ec6bae8389cc29a6ddbda1cabfa9a425b

Author: NicolasHug

torchvision/datasets/coco.py

@@ -10,7 +10,8 @@
 class CocoDetection(VisionDataset):
     """`MS Coco Detection <https://cocodataset.org/#detection-2016>`_ Dataset.
 
-    It requires the `COCO API to be installed <https://github.com/pdollar/coco/tree/master/PythonAPI>`_.
+    It requires `pycocotools <https://github.com/ppwwyyxx/cocoapi>`_ to be installed,
+    which could be installed via ``pip install pycocotools`` or ``conda install conda-forge::pycocotools``.
 
     Args:
         root (str or ``pathlib.Path``): Root directory where images are downloaded to.
@@ -65,7 +66,8 @@ def __len__(self) -> int:
 class CocoCaptions(CocoDetection):
     """`MS Coco Captions <https://cocodataset.org/#captions-2015>`_ Dataset.
 
-    It requires the `COCO API to be installed <https://github.com/pdollar/coco/tree/master/PythonAPI>`_.
+    It requires `pycocotools <https://github.com/ppwwyyxx/cocoapi>`_ to be installed,
+    which could be installed via ``pip install pycocotools`` or ``conda install conda-forge::pycocotools``.
 
     Args:
         root (str or ``pathlib.Path``): Root directory where images are downloaded to.