[Doc] add qwen3 reranker

[TingW09]

What this PR does / why we need it?

add qwen3 reranker tutorials

Does this PR introduce any user-facing change?

How was this patch tested?

• vLLM version: v0.12.0

[gemini-code-assist]

Code Review

This pull request adds documentation for the Qwen3 Reranker model and refactors the existing documentation for the Qwen3 Embedding model. The changes improve the structure and clarity of the documentation. However, there are a few issues that need to be addressed: several sections are left as placeholders, there's a typo in a URL that breaks it, and some internal links are broken due to incorrect casing in file paths. Addressing these will ensure the documentation is complete and accurate.

[gemini-code-assist]

The "Performance" section is added as a placeholder. For a documentation PR, it's important to provide complete information. If the data is not yet available, please consider adding a note with a link to a tracking issue or an estimated timeline for when this information will be provided.

[gemini-code-assist]

The links to the tutorials for Qwen3-Embedding and Qwen3-Reranker are broken due to incorrect casing in the filenames. The filenames use lowercase embedding and reranker, but the links use uppercase Embedding and Reranker. File paths are case-sensitive on many systems.

Suggested change

	| Qwen3-Embedding | ✅ | [Qwen3-Embedding tutorials](../../tutorials/Qwen3-Embedding.md) |||||||||||||||||||
	| Qwen3-Reranker | ✅ | [Qwen3-Reranker tutorials](../../tutorials/Qwen3-Reranker.md) |||||||||||||||||||
	| Qwen3-Embedding | ✅ | [Qwen3-Embedding tutorials](../../tutorials/Qwen3_embedding.md) |||||||||||||||||||
	| Qwen3-Reranker | ✅ | [Qwen3-Reranker tutorials](../../tutorials/Qwen3_reranker.md) |||||||||||||||||||

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