[FEATURE]: Add Dutch Language Support (nl_NL) & Add Language Addition Instructions to Documentation

[generic-user]

Hi,
Thanks for the great work on Codebook!
Would it be possible to add support for Dutch spelling dictionaries (nl_NL) in the Codebook extension? Many users, especially in the Netherlands and Belgium, would benefit from built-in Dutch spellchecking.

Additionally, it would be extremely helpful to include instructions in the README on how maintainers or users can add support for new languages. This could include:

Where/how to obtain compatible dictionary files

How to reference and configure them in the project

Any npm package instructions or linking steps for integration

This guidance would lower the threshold for community contributions and help users help themselves if their language is currently unsupported.

Thank you for considering!

[bartheerman]

👍

[blopker]

Hey! Thank you for the kind words.

I just merged this PR with nl_nl added: #121 If you know of a better dictionary than the one at https://github.com/wooorm/dictionaries/tree/main/dictionaries/nl, I can include that instead. The ones in this collection just seem to work well.

Adding a new dictionary is pretty quick, so I hadn't made instructions yet. However, it's a good idea, so I added some in that PR as well. I'll put out a new release soon!