Is it possible to add a language to codimd's spell check?

## Is it possible to add a language to codimd's spell check?

I have searched for a long time among the issues but I have not found a how to for this question.
In particular this issue https://github.com/hackmdio/codimd/issues/647 has been closed since February 5, 2020, and I didn't want to reopen it.
(I see there are many dictionaries available for spell check: https://github.com/wooorm/dictionaries)

I deployed codimd via docker-compose
(very similar to https://github.com/hackmdio/codimd/blob/develop/deployments/docker-compose.yml)

There are currently 5 supported languages in my installation:
- English US and UK
- German
- German DE and CH

Looking inside the docker container filesystem, I see that the 5 dictionaries are here:

```
hackmd@b12548abf616:~/app$ find -iname "*.dic"
./public/build/dictionary-en-gb/index.dic
./public/build/dictionary-de/index.dic
./public/build/dictionary-de-at/index.dic
./public/build/dictionary-de-ch/index.dic
./public/vendor/codemirror-spell-checker/en_US.dic
```

So it seems like en_US.dic is hardcoded in codemirror, while the other 4 seem to be "installed".
Is there a way to add some other language dictionaries?