merge: minor usepowerof2sizes correction merge

Author: Sam Kleinman

source/reference/mongodump.txt

@@ -128,7 +128,7 @@ Options
 
    Use the :option:`--collection` option to specify a collection for
    :program:`mongodump` to backup. If you do not specify a collection,
-   this options copies all collections in the specified database or
+   this option copies all collections in the specified database or
    instance to the dump files. Use this option to backup or copy a
    smaller subset of your data.
 

source/reference/mongooplog.txt

@@ -15,7 +15,7 @@ Synopsis
 the :term:`replication` :term:`oplog` of a remote server, and applies
 them to the local server. This capability supports certain classes of
 real-time migrations that require that the source server remain online
-and operation throughout the migration process.
+and in operation throughout the migration process.
 
 Typically this command will take the following form:
 
@@ -151,10 +151,10 @@ Options
 .. option:: --collection <collection>, -c <c>
 
    Use the :option:`--collection` option to specify a collection for
-   :program:`mongooplog` to backup. If you do not specify a collection,
-   this options copies all collections in the specified database or
-   instance to the dump files. Use this option to backup or copy a
-   smaller subset of your data.
+   :program:`mongooplog` to write data to. If you do not specify a collection,
+   :program:`mongooplog` will apply operations that apply to all
+   collections that appear in the oplog in the specified database. 
+   Use this option to migrate a smaller subset of your data.
 
 .. option:: --fields [field1[,field2]], -f [field1[,field2]]