fix method db.revokeRolesFromRole() malformed link

Author: andf-mongodb

source/reference/method/db.revokeRolesFromRole.txt

@@ -17,13 +17,13 @@ Definition
 
    Removes the specified inherited roles from a role.
 
-   The :method:`revokeRolesFromRole` method uses the following syntax:
+   The :method:`db.revokeRolesFromRole()` method uses the following syntax:
 
    .. code-block:: javascript
 
       db.revokeRolesFromRole( "<rolename>", [ <roles> ], { <writeConcern> } )
 
-   The :method:`revokeRolesFromRole` method takes the following arguments:
+   The :method:`db.revokeRolesFromRole()` method takes the following arguments:
 
 
    .. list-table::