Add missing ModelOutput subclass return type hints

[tomaarsen]

What does this PR do?

This PR adds missing ModelOutput subclass return type hints. I'm running an analysis on the Model classes to see what kind of outputs are used for the various modalities, and I noticed a handful of architectures were missing them.

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Did you read the contributor guideline,
  Pull Request section?
• Was this discussed/approved via a Github issue or the forum? Please add a link
  to it if that's the case.
• Did you make sure to update the documentation with your changes? Here are the
  documentation guidelines, and
  here are tips on formatting docstrings.
• Did you write any new necessary tests?

Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR.

@ArthurZucker

• Tom Aarsen

[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.

[github-actions]

[For maintainers] Suggested jobs to run (before merge)

run-slow: dac, deepseek_vl, deepseek_vl_hybrid, flava, grounding_dino, janus, maskformer, mm_grounding_dino, tvp, udop

[tomaarsen]

I fixed the merge conflicts. I totally forgot about this PR, but it should still be valuable to improve the typings somewhat.

• Tom Aarsen

[vasqu]

LGTM, I'm just wondering whether you only want to target the base model with this PR / how consistent this needs to be, e.g.

transformers/src/transformers/models/mm_grounding_dino/modeling_mm_grounding_dino.py

Line 2394 in b25d987

class MMGroundingDinoForObjectDetection(MMGroundingDinoPreTrainedModel):

has no output type

[tomaarsen]

@vasqu The script I wrote to check the type hints indeed only checked the base models, also because Sentence Transformers will in the future rely on the type hints of the base models. Extending it to the non-base classes would be nice, but I don't have the bandwidth for that now, as I'm aiming to get #42564 ready before the full v5.

• Tom Aarsen

[vasqu]

Gotcha, makes sense then. Let's merge, having more typing is better than nothing in the first place