Ignore message type "last-prompt"

```
Line 7 of .../3591eba5-5fd1-4c5d-8d84-21b16a901be3.jsonl is not a recognised message type: {"type":"last-prompt","lastPrompt":"Which 
command (awk, ruby) can I use to show all lines after the line containing","sessionId":"3591eba5-5fd1-4c5d-8d84-21b16a901be3"}
```

It's apparently the new last line of a .jsonl file... Can be ignored.