fixed name of coco detection dataset. (#328)

Author: kashif

torchvision/datasets/coco.py

@@ -80,7 +80,7 @@ def __len__(self):
 
 
 class CocoDetection(data.Dataset):
-    """`MS Coco Captions <http://mscoco.org/dataset/#detections-challenge2016>`_ Dataset.
+    """`MS Coco Detection <http://mscoco.org/dataset/#detections-challenge2016>`_ Dataset.
 
     Args:
         root (string): Root directory where images are downloaded to.