docs: add a how-to on subgraph transform state (#1595)

* docs: add a how-to on subgraph transform state

---------

Co-authored-by: isaac hershenson <ihershenson@hmc.edu>
Co-authored-by: Isaac Francisco <78627776+isahers1@users.noreply.github.com>

docs/_scripts/copy_notebooks.py

@@ -31,6 +31,7 @@ _MANUAL = {
         "pass_private_state.ipynb",
         "memory/manage-conversation-history.ipynb",
         "subgraphs-manage-state.ipynb",
+        "subgraph-transform-state.ipynb",
         "memory/delete-messages.ipynb",
         "memory/add-summary-conversation-history.ipynb",
         "persistence_postgres.ipynb",

docs/docs/how-tos/index.md

@@ -67,6 +67,7 @@ These guides show how to use different streaming modes.
 
 - [How to create subgraphs](subgraph.ipynb)
 - [How to manage state in subgraphs](subgraphs-manage-state.ipynb)
+- [How to transform inputs and outputs of a subgraph](subgraph-transform-state.ipynb)
 
 ## State Management
 

docs/mkdocs.yml

@@ -163,6 +163,7 @@ nav:
       - Subgraphs:
           - Create subgraphs: how-tos/subgraph.ipynb
           - Manage state in subgraphs: how-tos/subgraphs-manage-state.ipynb
+          - Transform inputs and outputs of a subgraph: how-tos/subgraph-transform-state.ipynb
       - State Management:
           - Use Pydantic model as state: how-tos/state-model.ipynb
           - Use a context object in state: how-tos/state-context-key.ipynb