docs: added aw-import-screentime to importers page

Author: ErikBjare

src/importers.rst

@@ -7,6 +7,7 @@ There aren't many yet, but here are some attempts:
 
 - :gh-aw:`aw-import-ical`, supports importing from ``.ical`` files or syncing with Google Calendar.
 - :gh-aw:`aw-importer-smartertime`, imports from `smartertime`_ (Android time tracker).
+- :gh-aw:`aw-import-screentime`, attempt at importing from macOS's Screen Time (and potentially iOS through syncing)
 - LastFM importer, :gh-user:`ErikBjare` has code for it somewhere, ask him if you're interested.