[DOC] Remove qwen3 dense w4a8 tutorial

[22dimensions]

modelslim doesn't support w4a8 quantization for dense model and the performance isn’t great, so remove this tutorial.

What this PR does / why we need it?

modelslim doesn't support w4a8 quantization for dense model right now and the performance of w4a8 dense model isn’t great, so remove this tutorial. Maybe replace this tutorial with w4a8 for moe model.

Does this PR introduce any user-facing change?

No

How was this patch tested?

CI

• vLLM version: v0.11.0rc3
• vLLM main: vllm-project/vllm@releases/v0.11.1

[github-actions]

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[gemini-code-assist]

Code Review

This pull request removes the tutorial for Qwen3 dense W4A8 quantization, which is appropriate given that the feature is not well-supported. However, the change is incomplete as it leaves a broken link in the documentation's table of contents. I have added a comment with details on how to fix this.

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.