fix: Regex match for links

[hoxbro]

The previous regex was too greedy, causing poor extraction when multiple links were provided and only the last one was a .ipynb link.

Previous:

New:

[HoloViews](https://holoviews.org) ([Interactivity](3_Interactivity.ipynb)).


(\[[^\]]+\]\()([^)\s]+\.ipynb)((?:#[^)\s]*)?\))

(\[.+?\]\()(.+?\.ipynb)(#*?.*?\))

Using: https://regex101.com/

Observed problem: