ReActive Agents w/ Context + updated stale link (run-llama#10058)

* Added context for agents, updated a stale link in CONTRIBUTING.md, and added a notebook to demo a react agent with context.

* Resolved issues in notebook.

* Fixed typo and added some more comments for kapa

* Added demo notebook to module_guides

Author: no-dice-io

CONTRIBUTING.md

@@ -333,7 +333,7 @@ make test
 For changes that involve entirely new features, it may be worth adding an example Jupyter notebook to showcase
 this feature.
 
-Example notebooks can be found in this folder: <https://github.com/jerryjliu/llama_index/tree/main/examples>.
+Example notebooks can be found in this folder: <https://github.com/run-llama/llama_index/tree/main/docs/examples>.
 
 ### Creating a pull request