Update chatbot.ipynb (#23688)

DOC: missing parenthesis #23687

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docs/docs/tutorials/chatbot.ipynb

@@ -261,7 +261,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "After that, we can import the relevant classes and set up our chain which wraps the model and adds in this message history. A key part here is the function we pass into as the `get_session_history`. This function is expected to take in a `session_id` and return a Message History object. This `session_id` is used to distinguish between separate conversations, and should be passed in as part of the config when calling the new chain (we'll show how to do that."
+    "After that, we can import the relevant classes and set up our chain which wraps the model and adds in this message history. A key part here is the function we pass into as the `get_session_history`. This function is expected to take in a `session_id` and return a Message History object. This `session_id` is used to distinguish between separate conversations, and should be passed in as part of the config when calling the new chain (we'll show how to do that)."
    ]
   },
   {