Harrison/human in the loop (#776)

* add human in the loop examples

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docs/docs/concepts/low_level.md

@@ -269,6 +269,11 @@ When you use a checkpointer with a graph, you can interact with the state of tha
 This usually done when enabling different human-in-the-loop interaction patterns.
 When interacting with the checkpointer state, you must specify [thread identifiers](#threads)
 
+Each checkpoint has two properties:
+
+-**values**: This is the value of the state at this point in time.
+-**next**: This is a tuple of the nodes to execute next in the graph.
+
 ### Get state
 
 You can get the state of a checkpointer by calling `graph.get_state(config)`. The config should contain `thread_id`, and the state will be fetched for that thread.

docs/docs/how-tos/index.md

@@ -22,8 +22,10 @@ One of LangGraph's main benefits is that it makes human-in-the-loop workflows ea
 These guides cover common examples of that.
 
 - [How to add persistence ("memory") to your graph](persistence.ipynb)
-- [How to view and update graph state](time-travel.ipynb)
-- [How to add human-in-the-loop](human-in-the-loop.ipynb)
+- [How to add breakpoints](human_in_the_loop/breakpoints.ipynb)
+- [How to edit graph state](human_in_the_loop/edit-graph-state.ipynb)
+- [How to wait for user input](human_in_the_loop/wait-user-input.ipynb)
+- [How to view and update past graph state](human_in_the_loop/time-travel.ipynb)
 
 ## Streaming