Fix: (issue #14066) DOC: Summarization output broken (#14078)

- **Description:** : As described in the issue below, 
https://python.langchain.com/docs/use_cases/summarization  
I've modified the Python code in the above notebook to perform well. 

I also modified the OpenAI LLM model to the latest version as shown
below.
`gpt-3.5-turbo-16k --> gpt-3.5-turbo-1106`
This is because it seems to be a bit more responsive.
  - **Issue:** : #14066

docs/docs/use_cases/summarization.ipynb

@@ -181,7 +181,7 @@
    "source": [
     "We can use `chain_type=\"stuff\"`, especially if using larger context window models such as:\n",
     "\n",
-    "* 16k token OpenAI `gpt-3.5-turbo-16k` \n",
+    "* 16k token OpenAI `gpt-3.5-turbo-1106` \n",
     "* 100k token Anthropic [Claude-2](https://www.anthropic.com/index/claude-2)\n",
     "\n",
     "We can also supply `chain_type=\"map_reduce\"` or `chain_type=\"refine\"` (read more [here](/docs/modules/chains/document/refine))."
@@ -212,7 +212,7 @@
     "loader = WebBaseLoader(\"https://lilianweng.github.io/posts/2023-06-23-agent/\")\n",
     "docs = loader.load()\n",
     "\n",
-    "llm = ChatOpenAI(temperature=0, model_name=\"gpt-3.5-turbo-16k\")\n",
+    "llm = ChatOpenAI(temperature=0, model_name=\"gpt-3.5-turbo-1106\")\n",
     "chain = load_summarize_chain(llm, chain_type=\"stuff\")\n",
     "\n",
     "chain.run(docs)"
@@ -672,7 +672,7 @@
     "summarize_document_chain = AnalyzeDocumentChain(\n",
     "    combine_docs_chain=chain, text_splitter=text_splitter\n",
     ")\n",
-    "summarize_document_chain.run(docs[0])"
+    "summarize_document_chain.run(docs[0].page_content)"
    ]
   },
   {