0.13.0: Annotation improvements, keyboard shortcut

This release improves the annotation functionality introduced in 0.12.0:

• Annotations now show up on the page outline (where available), so that you can quickly jump between different ideas.
• Next to the article title there's now a progress bar tracking the number of annotations you made on the page.
• Annotations can be turned off via the "pen" icon in the top right.
• Fixed bugs like limits to the possible number of annotations per page.
• UX improvements like automatically focusing the text field of created annotations.

You can also now press Alt+C (or ⌥+C on Mac) on your keyboard to activate the extension anywhere! (this is configurable in the settings)

Hopefully, these improvements make it easier to read great articles more deeply! The next release will add a reading time indicator and keyboard shortcuts.