[Docs] Fix formatting issues in API docs: en-dashes and RST inline code syntax

[ooooo-create]

Summary

This PR fixes formatting issues found in 3 API documentation files under docs/api/paddle/.

Changes

1. docs/api/paddle/distributed/reduce_scatter_cn.rst

• Replaced en-dash (–, U+2013) with regular hyphen (-) in parameter descriptions for tensor and tensor_list parameters
• The en-dash was inconsistent with all other parameter descriptions in the same file and across the codebase

2. docs/api/paddle/distributed/stream/reduce_scatter_cn.rst

• Replaced en-dash (–, U+2013) with regular hyphen (-) in the tensor parameter description
• Same issue as above

3. docs/api/paddle/fft/Overview_cn.rst

• Fixed single backtick to double backtick for inline code: `X[(n+1)//2]` → X[(n+1)//2]
• Added missing space between inline code and following Chinese text
• Single backticks in RST create "interpreted text" (cross-references), while double backticks create inline literals (code). The surrounding text uses double backticks consistently (e.g., X[(n-1)//2] ), so this was an inconsistency

Standards Compliance

These fixes address violations of the documentation standards described in .github/copilot-instructions.md:

• RST syntax compliance: use double backticks for inline code literals
• Consistency in formatting within and across files

Generated by API Docs Checker

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🔄 Synced from https://github.com/StatefulDust/paddle-docs-agent/pull/13

[paddle-bot]

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[github-actions]

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• docs/api/paddle/distributed/reduce_scatter_cn.rst: 点击预览
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• docs/api/paddle/fft/Overview_cn.rst: 点击预览

[Copilot]

Pull request overview

该 PR 针对 docs/api/paddle/ 下的中文 API 文档进行小范围格式修复，主要解决 RST 行内代码与参数列表分隔符的排版一致性问题，以避免 Sphinx 渲染异常或风格不统一。

Changes:

• 将参数描述中的 en-dash（–）统一替换为常规连字符（-），与同文件其余参数列表风格一致
• 修复 RST 行内代码标记：将单反引号改为双反引号（inline literal），并补齐代码后与中文之间的空格

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
docs/api/paddle/fft/Overview_cn.rst	修复一处行内代码从 interpreted text 改为 inline literal，并补齐代码与中文间空格
docs/api/paddle/distributed/stream/reduce_scatter_cn.rst	将参数列表分隔符由 en-dash 改为 -，与同页其余参数一致
docs/api/paddle/distributed/reduce_scatter_cn.rst	将 tensor/tensor_list 参数分隔符由 en-dash 改为 -，统一格式

[SigureMo]

LGTMeow