Update src/oss/langchain/short-term-memory.mdx

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: TheovanKraay

src/oss/langchain/short-term-memory.mdx

@@ -124,16 +124,16 @@ os.environ["COSMOSDB_ENDPOINT"] = "your_cosmosdb_endpoint"
 os.environ["COSMOSDB_KEY"] = "your_cosmosdb_key"
 
 # Database and Container are created if they don't exist
-checkpointer = CosmosDBSaver(  # [!code highlight]
+with CosmosDBSaver(  # [!code highlight]
     database_name="your_database",  # [!code highlight]
     container_name="your_container"  # [!code highlight]
-)  # [!code highlight]
+) as checkpointer:  # [!code highlight]
 
-agent = create_agent(
-    "gpt-5",
-    [get_user_info],
-    checkpointer=checkpointer,  # [!code highlight]
-)
+    agent = create_agent(
+        "gpt-5",
+        [get_user_info],
+        checkpointer=checkpointer,  # [!code highlight]
+    )
 ```
 
 <Note>