docs: remove redundant language switch headers from markdown files

[mattheliu]

Motivation

To simplify and standardize documentation maintenance.
Currently, many Markdown files in docs/ include manually added bilingual path references such as:

[简体中文](../zh/best_practices/ERNIE-4.5-0.3B-Paddle.md)

However, the FastDeploy documentation site already supports language switching through configuration (/zh/, /en/), and these manual links lead to incorrect online URLs like:

https://paddlepaddle.github.io/FastDeploy/best_practices/zh/best_practices/ERNIE-4.5-0.3B-Paddle.md

which should be:

https://paddlepaddle.github.io/FastDeploy/zh/best_practices/ERNIE-4.5-0.3B-Paddle/

Therefore, this PR removes redundant bilingual path links from Markdown headers and bodies to avoid link errors and improve maintainability.

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Modifications

• Removed all manually added bilingual path references ([简体中文], [English]) in Markdown headers and bodies.
• Verified that all Markdown files remain accessible via the documentation site’s language-switching mechanism.
• No content or structure change to document bodies beyond removing redundant links.

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Usage or Command

N/A — Documentation-only change.

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Accuracy Tests

N/A — This PR does not affect model code or inference accuracy.

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Additional Notes

A follow-up RFC will be proposed to:

• Upgrade the FastDeploy documentation site to use mkdocs-material + GitHub Pages (aligned with PaddleOCR).
• Optimize multilingual routing and theme consistency.

Checklist

• Add at least a tag in the PR title.
  • Tag list: [[FDConfig],[APIServer],[Engine], [Scheduler], [PD Disaggregation], [Executor], [Graph Optimization], [Speculative Decoding], [RL], [Models], [Quantization], [Loader], [OP], [KVCache], [DataProcessor], [BugFix], [Docs], [CI], [Optimization], [Feature], [Benchmark], [Others], [XPU], [HPU], [GCU], [DCU], [Iluvatar], [Metax]]
  • You can add new tags based on the PR content, but the semantics must be clear.
• Format your code, run pre-commit before commit.
• Add unit tests. Please write the reason in this PR if no unit tests.
• Provide accuracy results.
• If the current PR is submitting to the release branch, make sure the PR has been submitted to the develop branch, then cherry-pick it to the release branch with the [Cherry-Pick] PR tag.

[paddle-bot]

Thanks for your contribution!