Add ability to get a list of supported pipeline tasks

[codesue]

What does this PR do?

This change adds the ability to programmatically get a list of supported pipeline tasks.

Currently, when new users want to know which tasks are supported in a pipeline, we have to reference the Pipelines documentation or parse the SUPPORTED_TASKS and TASK_ALIASES dictionaries. Being able to programmatically get a list of supported pipeline tasks would be more convenient since it requires less context switching and parsing.

Example usage:

>>> from transformers.pipelines import get_supported_tasks
>>> print(*get_supported_tasks(), sep=“\n”)
audio-classification
automatic-speech-recognition
conversational
feature-extraction
fill-mask
image-classification
image-segmentation
ner
object-detection
question-answering
sentiment-analysis
summarization
table-question-answering
text-classification
text-generation
text2text-generation
token-classification
translation
zero-shot-classification

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• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
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Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
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@LysandreJik @Narsil

[julien-c]

Thanks for the PR!

Off-topic from the actual PR but for background information, this is where the "canonical" list of pipelines (even outside of transformers) supported by the HuggingFace hub is stored: https://github.com/huggingface/huggingface_hub/blob/main/widgets/src/lib/interfaces/Types.ts

[LysandreJik]

Thank you for your PR, @codesue, this is useful! The failing tests are unrelated to your PR and are currently being fixed.

LGTM

[Narsil]

LGTM

[codesue]

Thanks for the reviews, everyone! And, wow, that was so fast! 🤩