Update source/core/sharding.txt

Author: epc

source/core/sharding.txt

@@ -159,7 +159,7 @@ A :term:`sharded cluster` has the following components:
      sharding, on a *per collection* basis. You *must* access all data
      in a sharded cluster via the :program:`mongos` instances as below.
      If you connect directly to a :program:`mongod` in a sharded cluster
-     you will see its fraction of cluster's data. The data on any
+     you will see its fraction of the cluster's data. The data on any
      given shard may be somewhat random: MongoDB provides no guarantee
      that any two contiguous chunks will reside on a single shard.