Pipelines snippets: add the inference call

[gary149]

To be discussed
One line away from having a complete snippet you can run by copy-pasting?

Idea from the transformers.js docs, where you can see the complete pipeline:

Should we update to this?

[osanseviero]

This looks simple for text but becomes trickier for audio/images or tasks such as zero-shot classification. If we do this, I would try to reuse the work done in https://github.com/huggingface/huggingface.js/blob/main/packages/tasks/src/snippets/python.ts