docs(ollama): Fix Documentation in `CallbackManager`, missing `])` (#15380)

- **Description:** This PR corrects a documentation error in the
`ollama` usage tutorial. Specifically, it fixes a missing `])` in the
`CallbackManager()` example, ensuring that the code snippet is
syntactically correct and can be successfully executed.
  - **Issue:** N/A
- **Dependencies:** No additional dependencies are required for this
change.
  - **Twitter handle:** My twitter is @yhzhu99

docs/docs/integrations/llms/ollama.ipynb

@@ -72,8 +72,8 @@
     "\n",
     "```\n",
     "llm = Ollama(\n",
-    "    model=\"llama2\"\n",
-    "    callback_manager=CallbackManager([StreamingStdOutCallbackHandler()\n",
+    "    model=\"llama2\",\n",
+    "    callback_manager=CallbackManager([StreamingStdOutCallbackHandler()]),\n",
     ")\n",
     "```"
    ]