DOCSP-48719: Update non-Mongo credential placeholders

Author: mcmorisi

source/security.txt

@@ -671,7 +671,7 @@ Windows
       .. code-block:: python
 
          client = pymongo.MongoClient("mongodb://<hostname>:<port>",
-                                       username="<db_username>",
+                                       username="<username>",
                                        authMechanism="GSSAPI",
                                        password="<db_password>",
                                        authMechanismProperties="SERVICE_NAME:<authentication service name>,
@@ -698,7 +698,7 @@ Windows
       .. code-block:: python
 
          client = pymongo.AsyncMongoClient("mongodb://<hostname>:<port>",
-                                           username="<db_username>",
+                                           username="<username>",
                                            authMechanism="GSSAPI",
                                            password="<db_password>",
                                            authMechanismProperties="SERVICE_NAME:<authentication service name>,
@@ -737,8 +737,8 @@ PLAIN SASL
       .. code-block:: python
 
          client = pymongo.MongoClient("mongodb://<hostname>:<port>",
-                                      username="<db_username>",
-                                      password="<db_password>",
+                                      username="<username>",
+                                      password="<password>",
                                       authMechanism="PLAIN",
                                       tls=True)
 
@@ -747,7 +747,7 @@ PLAIN SASL
 
       .. code-block:: python
 
-         uri = ("mongodb://<db_username>:<db_password>@<hostname>:<port>/?"
+         uri = ("mongodb://<username>:<password>@<hostname>:<port>/?"
                 "&authMechanism=PLAIN"
                 "&tls=true")
          client = pymongo.MongoClient(uri)
@@ -758,8 +758,8 @@ PLAIN SASL
       .. code-block:: python
 
          client = pymongo.AsyncMongoClient("mongodb://<hostname>:<port>",
-                                           username="<db_username>",
-                                           password="<db_password>",
+                                           username="<username>",
+                                           password="<password>",
                                            authMechanism="PLAIN",
                                            tls=True)
 
@@ -768,7 +768,7 @@ PLAIN SASL
 
       .. code-block:: python
 
-         uri = ("mongodb://<db_username>:<db_password>@<hostname>:<port>/?"
+         uri = ("mongodb://<username>:<password>@<hostname>:<port>/?"
                 "&authMechanism=PLAIN"
                 "&tls=true")
          client = pymongo.AsyncMongoClient(uri)