[AO3] Bookmarks that Bookmark

Isn't it odd that, despite the name, Archive of Our Own bookmarks never keep track of where you left off in a work? This script solves that by prepending bookmark descriptions with an indicator of what chapter you left off on.

By default, indicators will look something like:
- Left on Chapter 1 -

You can easily find and change the formatting of the indicators, but I would suggest understanding basic HTML before messing with anything.