change db_password

Author: lindseymoore

source/security/enterprise-auth.txt

@@ -276,7 +276,7 @@ mechanism:
 
       .. code-block:: java
 
-         MongoClient mongoClient = MongoClients.create("<username>:<db_password>@<hostname>:<port>/?authSource=$external&authMechanism=PLAIN");
+         MongoClient mongoClient = MongoClients.create("<username>:<password>@<hostname>:<port>/?authSource=$external&authMechanism=PLAIN");
 
    .. tab::
       :tabid: MongoCredential