Em Dash Block per peterus

Highlights paragraphs containing em dashes. Of course, em dashes alone are not a definitive indicator of AI use so please be responsible, but this extension should make it clear when someone is 'overusing' this character.

Features:
- Highlights paragraphs containing em-dashes with a red-black stripe. NOTE: Only looks at paragraph elements, this extension does not include em-dashes in other elements.