[Docs] reemove the incorrect enable_reasoning parameter

[yyzxw]

Purpose

vLLM does not have enable_reasoning parameter

Test Plan

Test Result

---

Essential Elements of an Effective PR Description Checklist

• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
• The test plan, such as providing test command.
• The test results, such as pasting the results comparison before and after, or e2e results
• (Optional) The necessary documentation update, such as updating supported_models.md and examples for a new model.
• (Optional) Release notes update. If your change is user facing, please update the release notes draft in the Google Doc.

[mergify]

Documentation preview: https://vllm--27550.org.readthedocs.build/en/27550/

[gemini-code-assist]

Code Review

This pull request correctly removes the --enable_reasoning parameter from the documentation, as it is not a valid vLLM CLI argument. The change is accurate and improves the documentation.

While reviewing, I discovered a critical bug in the HunyuanA13BReasoningParser that prevents the enable_thinking: false feature from working as intended. The is_reasoning_end method does not correctly process prompt tokens, leading to incorrect behavior when reasoning is disabled via request parameters. I've added a comment with a suggested fix for this issue.

Also, a minor note: the pull request title has a typo ("reemove" instead of "remove").

Overall, the documentation change is good to merge, but I highly recommend addressing the identified bug to ensure the Hunyuan model's reasoning features work correctly.

[chaunceyjiang]

--enable_reasoning is deprecated.

ref #17452

[DarkLight1337]

Thanks for the cleanup