doc: improve napi formatting
This addresses two nits:
- Bullet points that span over multiple lines should be indented consitently. Otherwise they are not always properly highlighted.
- Lines breaks after titles improve the readability.
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
tests and/or benchmarks are included -
documentation is changed or added -
commit message follows commit guidelines