Merge pull request #16 from steamship-core/doc-fix

docs: fix document_loaders index

Author: douglas-reid

docs/adapters/document_loaders.rst

@@ -18,4 +18,4 @@ The following notebook provides a demonstration of how to use the SteamshipLoade
    :name: Document Loaders
    :hidden:
 
-   ./document_loaders/how_to_guides.rst
+   ./document_loaders/how_to_guide.ipynb