Add docs on zeroshot image classification prompt templates

[aliencaocao]

What does this PR do?

Adds documentation on prompt templates for Zero Shot Image Classification tasks so that the output results match pipelines and are also correct. Not applying the template can lead to greatly worsened accuracy.

Fixes #30951

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
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  here are tips on formatting docstrings.
• Did you write any new necessary tests?

Who can review?

@amyeroberts

[aliencaocao]

i have a PR that adds support for siglip training coming up so would be great if this could be merged asap so the docs don't merge conflict

[amyeroberts]

i have a PR that adds support for siglip training coming up so would be great if this could be merged asap so the docs don't merge conflict

@aliencaocao I appreciate that you want to have PRs merged in as soon as possible (we do too!) but managing conflicts for other PRs isn't something that we will consider, unless it's also for transformers something we want to merge in and linked to.

[amyeroberts]

Thanks for contributing to improving the docs!

I'm important to distinguish between what the user must feed to the model, and a useful example. The "This is a photo of {}" prompt just helps replicate the values from the pipeline, but it's not a requirement and can in fact be changed in the pipeline too.

[aliencaocao]

@amyeroberts heads up i've made the changes already

[amyeroberts]

Thanks!

Just two tiny nits

[aliencaocao]

Merged your suggestions

[amyeroberts]

@aliencaocao Can you try rebasing to include the latest changes upstream? This should resolve some of the issues on the CI runs

[aliencaocao]

@amyeroberts hi somehow the workflows arent getting triggered?

[HuggingFaceDocBuilderDev]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

[amyeroberts]

@aliencaocao We've had a few issues with tests triggering on circle CI today. I'm not 100% sure of the cause, but other PRs which have blocked workflows are now working. Could you try triggering a new run? git commit --allow-empty -m "Trigger CI"

[aliencaocao]

@amyeroberts its ready now

[amyeroberts]

Thanks for updating the docs and your patience with the CI!