Improve readability of notebooks (#2200)

* Improve readability

* Update context_handling.py

update line breaks according to comment of reviewer

* Update agentchat_groupchat_finite_state_machine.ipynb

corrected sentence according to comment of reviewer

* Update autogen/agentchat/contrib/capabilities/context_handling.py

Co-authored-by: Jack Gerrits <jackgerrits@users.noreply.github.com>

---------

Co-authored-by: Shaokun Zhang <shaokunzhang529@gmail.com>
Co-authored-by: Jack Gerrits <jackgerrits@users.noreply.github.com>