Miscellaneous the/a typos cleanup

source/core/master-slave.txt

@@ -118,7 +118,7 @@ after ten second pause, when the slave falls out of sync with the
 master. With :option:`--autoresync <mongod --autoresync>` specified,
 the slave will only attempt to re-sync once in a ten minute period.
 
-To prevent these situations you should specify the a larger oplog when
+To prevent these situations you should specify a larger oplog when
 you start the :setting:`master` instance, by adding the
 :option:`--oplogSize <mongod --oplogSize>` option when starting
 :program:`mongod`. If you do not specify

source/reference/database-profiler.txt

@@ -225,7 +225,8 @@ operation.
 .. data:: system.profile.responseLength
 
    The length in bytes of the operation's result document. A large
-   :data:`~system.profile.responseLength` can affect performance. To limit the size of a the
+   :data:`~system.profile.responseLength` can affect performance.
+   To limit the size of the
    result document for a query operation, you can use any of the
    following:
 

source/reference/projection/slice.txt

@@ -42,7 +42,7 @@ $slice (projection)
    This operation returns the last five items in array.
 
    The following examples specify an array as an argument to
-   slice. Arrays take the form of ``[ skip , limit ]``, where the
+   :projection:`$slice`. Arrays take the form of ``[ skip , limit ]``, where the
    first value indicates the number of items in the array to skip and
    the second value indicates the number of items to return.
 

source/tutorial/backup-small-sharded-cluster-with-mongodump.txt

@@ -27,7 +27,7 @@ Capture Data
 
 .. note:: 
 
-   If you use :program:`mongodump` without specifying the a database
+   If you use :program:`mongodump` without specifying a database
    or collection, :program:`mongodump` will capture collection data
    *and* the cluster meta-data from the :ref:`config servers
    <sharding-config-server>`.