Fix OpenAI client usage example for embeddings

[ZahraDehghani99]

Title

docs(tei): fix OpenAI client usage example for embeddings

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PR Description

This PR updates the documentation for using the OpenAI Python client with TEI’s OpenAI-compatible API.
The previous example incorrectly set the base_url to /v1/embeddings, which caused errors.
It also did not mention that the OpenAI client requires an api_key argument (even if unused by TEI).

Changes made:

• Corrected the base_url to http://localhost:8080/v1
• Added api_key="fake" to satisfy the OpenAI client requirements
• Updated the example to print response.data[0].embedding for clarity

Motivation:
Improve usability of the TEI docs by providing a working out-of-the-box example for developers who want to use the OpenAI client with TEI.

Fixes:
N/A (documentation improvement)

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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?
• Did you make sure to update the documentation with your changes?
• Tests not applicable (docs-only change).

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Who can review?

Tagging maintainer for review:
@Narsil

[alvarobartt]

Hey @ZahraDehghani99 thanks a lot for the PR! I've included some extra comments, but other than that LGTM 🤗

[ZahraDehghani99]

Hey @ZahraDehghani99 thanks a lot for the PR! I've included some extra comments, but other than that LGTM 🤗

Thank you so much @alvarobartt for all your helpful suggestions! I’ve applied all of them and cleaned up the examples, including fixing the backticks and removing the accidentally added duplicate from GitHub UI. I also added the port number in the curl request so it works correctly. Please let me know if there’s anything else I should adjust 😊

[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.

[alvarobartt]

Thanks @ZahraDehghani99, merging to main now 🔥