fix(mongodb): create user2

Author: ldecarvalho-doc

pages/managed-mongodb-databases/how-to/manage-users.mdx

@@ -63,15 +63,24 @@ You can create more users and grant them pre-set roles via the [Scaleway Managed
       -d '{
         "name": "<username>",
         "password": "<password>",
+    }' \
+      "https://api.scaleway.com/mongodb/v1alpha1/regions/fr-par/instances/{instance_id}/users"
+    ```
+
+    You should get a response like the following:
+    ```
+    {
+        "name": "<username>",
+        "password": "<password>",
         "roles": [
             {
-                "role": "string",
-                "database": "string",
+                "role": "<username>",
+                "database": "<password>",
                 "any_database": true
             }
         ]
-    }' \
-      "https://api.scaleway.com/mongodb/v1alpha1/regions/fr-par/instances/{instance_id}/users"
+    }
     ```
 
+### How to apply a role to a user