chore(docs): Consolidate hooks for copy markdown and notebooks (#5459)

Consolidating the hooks to avoid duplication of logic

We need this change for consolidating js and python content: we need include-markdown to run as a mkdocs plugin before our pipeline (rather than as markdown extension which runs after our hooks plugin).

docs/docs/tutorials/get-started/5-customize-state.md

@@ -221,7 +221,7 @@ Manual state updates will [generate a trace](https://smith.langchain.com/public/
 
 Check out the code snippet below to review the graph from this tutorial:
 
-{!snippets/chat_model_tabs.md!}
+{% include-markdown "../../../snippets/chat_model_tabs.md" %}
 
 <!---
 ```python