Note features

[sanghaya]

Hi Jerome,

Thanks for the amazing library. I am thinking of adding note functionality similar to BeanNote (https://chrome.google.com/webstore/detail/beanote-note-taking-on-we/nikccehomlnjkmgmhnieecolhgdafajb).

I can try to implement it similar to how the current in-place highlight works, but I was wondering if you had any thoughts or recommendations. Happy to open pull requests once it's implemented.

Best