Allow the page for pdf annotations to be renamed

The page for annotations in a PDF called <name>.pdf is always hls__<name>.(md|org). This is annoying when you have more than one set of slides called 01-intro.pdf in different folders (e.g., from multiple university courses).

It would be great if the name of the annotation page could be changed. In my opinion, the ideal place to store this position is the <name>.edn file that is created anyway for the annotations.