Support nested block comments (a PICO-8 feature, but not a Lua feature)
I am using the luamin command to try and compress my cart. It does a great job of shrinking the compressed size, but it actually grows my token count by a few hundred (putting it over the limit):

Pre luamin: 8010 tokens
Post-luamin: 8304 tokens

However, the picotool reports no change in token count (and the counts themselves are wrong):

```
C:\Users\Matt\Downloads\picotool-master>py ./picotool-master/p8tool stats ../../AppData/Roaming/pico-8/carts/mario_new.p8
advanced micro platformer (mario_new.p8)
@matthughson
- version: 16
- lines: 2550
- chars: 59633
- tokens: 9304
- compressed chars: 23048


C:\Users\Matt\Downloads\picotool-master>
C:\Users\Matt\Downloads\picotool-master>py ./picotool-master/p8tool stats ../../AppData/Roaming/pico-8/carts/mario_new_fmt.p8
mario_new_fmt.p8
- version: 8
- lines: 1930
- chars: 31766
- tokens: 9304
- compressed chars: 12466
```

I have upload the p8 cart file here if you wish to reproduce the issue: [mario_new.p8](https://pastebin.com/CDDMirzU)

Is this a known issue? Is there any known work around?