feat: Add Dutch (nl-NL) translations.json and update config.json

[jeannotdamoiseaux]

Purpose

This update adds support for the Dutch language in the application. It includes translations of the user interface and labels to Dutch, enabling a more accessible experience for Dutch-speaking users.

Does this introduce a breaking change?

When developers merge from main and run the server, azd up, or azd deploy, will this produce an error?
If you're not sure, try it out on an old environment.

[ ] Yes
[ X ] No

Does this require changes to learn.microsoft.com docs?

This repository is referenced by this tutorial
which includes deployment, settings and usage instructions. If text or screenshot need to change in the tutorial,
check the box below and notify the tutorial author. A Microsoft employee can do this for you if you're an external contributor.

[ ] Yes
[ X ] No

Type of change

[ ] Bugfix
[ X ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Documentation content changes
[ ] Other... Please describe:

Code quality checklist

See CONTRIBUTING.md for more details.

• The current tests all pass (python -m pytest).
• I added tests that prove my fix is effective or that my feature works
• I ran python -m pytest --cov to verify 100% coverage of added lines
• I ran python -m mypy to check for type errors
• I either used the pre-commit hooks or ran ruff and black manually on my code.

[jeannotdamoiseaux]

I encountered one test failure when running python -m pytest, but this issue appears unrelated to my changes.

The failing test is:
FAILED tests/test_prepdocslib_textsplitter.py::test_sentencetextsplitter_list_parse_and_split - assert 1 > 1

[jeannotdamoiseaux]

@pamelafox Could you review this PR?

[pamelafox]

@jeannotdamoiseaux Thanks for the PR! A few questions:

1. I assume that you wrote these translations yourself, i.e. you're a native Dutch speaker
2. Will you be available to translate strings in the future, i.e. can I tag you on PRs that add new Dutch strings? I don't know if I have any Dutch speaking colleagues, so we need to make sure we have a strategy to continue support for nl
3. Can you provide a screenshot of the app working with nl? Sometimes folks have contributed strings but not actually confirmed that they worked in the app, so I want to make sure.

[jeannotdamoiseaux]

@jeannotdamoiseaux Thanks for the PR! A few questions:

1. I assume that you wrote these translations yourself, i.e. you're a native Dutch speaker
2. Will you be available to translate strings in the future, i.e. can I tag you on PRs that add new Dutch strings? I don't know if I have any Dutch speaking colleagues, so we need to make sure we have a strategy to continue support for nl
3. Can you provide a screenshot of the app working with nl? Sometimes folks have contributed strings but not actually confirmed that they worked in the app, so I want to make sure.

1. Yes, I’m a native Dutch speaker and did these translations myself.
2. Sure, feel free to tag me in future PRs! I’m available to assist with new Dutch translations.
3. I’ll upload a screenshot demonstrating the app with Dutch translations by tomorrow.

[pamelafox]

Great, tests are passing on CI, so I'll approve and merge once screenshot is available. Thanks so much!

[jeannotdamoiseaux]

Great, tests are passing on CI, so I'll approve and merge once screenshot is available. Thanks so much!

Does this look good to you?

[pamelafox]

Great, thank you!

[jeannotdamoiseaux]

Great, thank you!

Excellent, thank you! I appreciate it. I’ll have a few more PRs coming your way soon!