minor: fixing broken link in sharding administration

Author: Sam Kleinman

source/administration/sharding.txt

@@ -512,7 +512,7 @@ To modify the chunk size, use the following procedure:
 
 .. note::
 
-   The :setting:`chunkSize` and :option:`--chunkSize <mongos>`
+   The :setting:`chunkSize` and :option:`--chunkSize <mongos --chunkSize>`
    options, passed at runtime to the :program:`mongos` **do not**
    affect the chunk size after you have initialized the cluster.