fix formatting glitch and the affect of the doc.

Author: epc

source/reference/mongod.txt

@@ -568,7 +568,7 @@ Sharding Cluster Options
    Declares that this :program:`mongod` instance serves as the
    :term:`config database` of a sharded cluster. When running with
    this option, clients will not be able to write data to any database
-   other than ``config`` and ``admin. The default port for
+   other than ``config`` and ``admin``. The default port for
    :program:`mongod` with this option is ``27019`` and
    :program:`mongod` writes all data files to the ``/configdb``
    sub-directory of the :option:`--dbpath` directory.
@@ -577,7 +577,7 @@ Sharding Cluster Options
 
    Configures this :program:`mongod` instance as a shard in a
    partitioned cluster. The default port for these instances is
-   ``27018``.  The only affect of :option:`--shardsvr` is to change
+   ``27018``.  The only effect of :option:`--shardsvr` is to change
    the port number.
 
 .. option:: --noMoveParanoia