✨ Add block assignment functionality in jinja package.

[pweglik]

This PR implements functionality of block assignments (https://jinja.palletsprojects.com/en/stable/templates/#block-assignments) in lexer, parser and engine=
I felt encouraged by the reply here:
#1087 (comment)

It was necessary to parse some chat_templates e.g. https://huggingface.co/MadeAgents/Hammer2.1-1.5b/blob/main/tokenizer_config.json (nicely formatted chat_template: https://pastebin.com/xBmhbwLi)

Let me know if you have any feedback.

[xenova]

Thanks so much! This is very useful and the PR looks clean 👍

Maybe it's worth adding a unit test for a very simple test string that tests just this functionality? To be added in

huggingface.js/packages/jinja/test/templates.test.js

Line 7 in 1a63901

const TEST_STRINGS = {

[pweglik]

Good suggestion @xenova, I've added a simple test 👍

[pweglik]

I've also added a simple test for string array filter.

[xenova]

Flawless PR! Thanks a ton!

Failing lint is unrelated to this PR - could you merge main into your branch? I'll re-run CI and merge when all is green.

[pweglik]

I've already rebased pweglik:main onto huggingface:main
Thanks a lot 😄

[xenova]

Ah yes you are right! Fixed by #1348 (& ran pnpm format).

Thanks again.