add links (#1027)

docs/modules/chains/combine_docs_how_to.rst

@@ -17,6 +17,12 @@ The examples here are all end-to-end chains for working with documents.
 
 `Vector DB Question Answering with Sources <./combine_docs_examples/vector_db_qa_with_sources.html>`_: A walkthrough of how to use LangChain for question answering (with sources) over a vector database.
 
+`Graph Question Answering <./combine_docs_examples/graph_qa.html>`_: A walkthrough of how to use LangChain for question answering (with sources) over a graph database.
+
+`Chat Vector DB <./combine_docs_examples/chat_vector_db.html>`_: A walkthrough of how to use LangChain as a chatbot over a vector database.
+
+`Analyze Document <./combine_docs_examples/analyze_document.html>`_: A walkthrough of how to use LangChain to analyze long documents.
+
 
 .. toctree::
    :maxdepth: 1

docs/modules/utils/generic_how_to.rst

@@ -15,6 +15,10 @@ The utilities listed here are all generic utilities.
 
 `SerpAPI <./examples/serpapi.html>`_: How to use the SerpAPI wrapper to search the web.
 
+`Bing Search <./examples/bing_search.html>`_: How to use the Bing search wrapper to search the web.
+
+`Wolfram Alpha <./examples/wolfram_alpha.html>`_: How to use the Wolfram Alpha wrapper to interact with Wolfram Alpha.
+
 
 .. toctree::
    :maxdepth: 1