fix bad link to hashed index doc

Author: kay-kim

source/reference/command/shardCollection.txt

@@ -67,7 +67,7 @@ Hashed Shard Keys
 ~~~~~~~~~~~~~~~~~
 
 :ref:`Hashed shard keys <sharding-hashed-sharding>` use a
-:doc:`hashed index </core/index-hashed/#index-hashed-index>` of a
+:doc:`hashed index </core/index-hashed>` of a
 single field as the shard key.
 
 Use the form ``{field: "hashed"}`` to specify a hashed shard key.