fix link (#2123)

docs/modules/chains/index_examples/summarize.ipynb

@@ -7,7 +7,7 @@
    "source": [
     "# Summarization\n",
     "\n",
-    "This notebook walks through how to use LangChain for summarization over a list of documents. It covers three different chain types: `stuff`, `map_reduce`, and `refine`. For a more in depth explanation of what these chain types are, see [here](../combine_docs.md)."
+    "This notebook walks through how to use LangChain for summarization over a list of documents. It covers three different chain types: `stuff`, `map_reduce`, and `refine`. For a more in depth explanation of what these chain types are, see [here](https://docs.langchain.com/docs/components/chains/index_related_chains)."
    ]
   },
   {