tiup: tiup-command-completion 已支持四种shell补全

[shawn0915]

Change Request

This repository is ONLY used to solve problems related to DOCS-CN. For other issues (TiDB, TiKV, etc), please move to other repositories.

Please answer the following questions before submitting your issue. Thanks!

1. Describe what you find is inappropriate or missing in the existing docs.

目前已支持四种 shell (bash / zsh / fish / powershell) 生成自动补全脚本

2. Describe your suggestion or addition.

3. Provide some reference materials (documents, websites, etc) if you could.

ref. https://asktug.com/t/topic/1020959 https://github.com/pingcap/docs-cn/pull/16166#discussion_r1461284562

[Oreoxmt]

@kaaaaaaang Could you please take a look at this issue and create a doc PR to add it?