Aesthetic and styling fixes to the SDK reference docs:
- [x] Improve readability of LanceDB in the header
- [x] Make header more compact, and consistent in gradient color with
the main website/docs
- [x] Updated favicon to match with the docs page
- [x] Enable permalink display to allow users to get anchor links to
each function/method
- [x] Point readers to the main docs at
[docs.lancedb.com](https://docs.lancedb.com)
