Add `abstract`, `annote`, and `genre` to documentation

[mkdjr]

Documents the changes made in PR https://github.com/typst/hayagriva/pull/102.

@Drodt, could you contribute an example for annote? I am not familiar with this annotation and was hoping you could provide an example.

[Drodt]

I recommend:

annote: The researchers at NYU explore in this paper ...

which is from https://www.bibtex.com/f/annote-field/

[mkdjr]

Thanks for the example; added!