minor: fixing cross reference

Author: Sam Kleinman

source/core/sharded-cluster-internals.txt

@@ -461,7 +461,7 @@ always has capacity to accommodate additional data.
 You can also configure a "maximum size" for any shard when you add the
 shard using the ``maxSize`` parameter of the :dbcommand:`addShard`
 command. This will prevent the :term:`balancer` from migrating chunks
-to the shard when the value of :data:`mem.mapped <serverStatus.mem.mapped>` 
+to the shard when the value of :data:`~serverStatus.mem.mapped`
 exceeds the ``maxSize`` setting.
 
 .. seealso:: :ref:`sharded-cluster-config-max-shard-size` and