add note that restoreDbUsersAndRoles requires dumpDbUsersAndRoles (#182)

* add note that restoreDbUsersAndRoles requires dumpDbUsersAndRoles

* How about spelling words correctly?

Author: MongoCaleb

source/mongorestore.txt

@@ -725,14 +725,13 @@ Options
 
    .. note::
 
-      The :option:`--restoreDbUsersAndRoles` option cannot be used if
-      specifying the ``admin`` database to the :option:`--db
-      <mongorestore --db>` option, and attempting to do so will result
-      in an error. Restoring the ``admin`` database by specifying
-      :option:`--db admin <mongorestore --db>` to
-      ``mongorestore`` already restores all users and roles.
-   
+      - You can only use ``--restoreDbUsersAndRoles`` on a database dump that 
+        was created with the :option:`--dumpDbUsersAndRoles` option. 
 
+      - Restoring the ``admin`` database by specifying 
+        :option:`--db admin <mongorestore --db>` automatically restores all 
+        users and roles. You cannot use ``--restoreDbUsersAndRoles`` 
+        on the ``admin`` database, and attempting to do so results in an error. 
 
 .. option:: --writeConcern=<document>