Include note taking software section

[sungwoncho]

I would like to suggest that we include a note taking software section to the list. Digital notebooks are ubiquitous and something that most of us need. Therefore, including privacy-respecting alternatives in the list can help many people to protect their data further. e.g. #42

What do you think about it?

[nikivdev]

I agree. I'd love a PR for it.

[YerinAlexey]

Some recommendations for this category:

• Markor
• Tasks.org
• Simple Notes is also pretty good but not as feature-rich as Markor