NotifyBecomingIdle is only notified at the first idle tick, so `countdown` is not set when TickIdle checks it at first game tick. Therefore, we let TickIdle return early at first game tick to avoid that.
- Typo in documentation ("proximitry").
- Add spaces between sentences.
- Remove most occurrences of " " (two spaces) unless clearly used as indendation
- Punctuation (although no fullstop after filenames like "notifications.yaml").
