Enable no-unused-vars lint

This is the big one. Probably needs thorough review to make sure I
didn't accidentally remove any setInterval or fetch calls.

public/scripts/bookmarks.js

@@ -28,7 +28,6 @@ import { createTagMapFromList } from "./tags.js";
 import {
     delay,
     getUniqueName,
-    stringFormat,
 } from "./utils.js";
 
 export {