Add translated document: glsl-extension.zh.md

[whyb]

Add translated document: glsl-extension.zh.md

[tencent-adm]

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1 out of 2 committers have signed the CLA.

✅ nihui
❌ whyb
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[whyb]

@nihui 这个translate版就先维持基于原滋原味的 glsl-extension.md 嘛🙈，至于qgroup所说的后面要补充的前置知识分享再分到其他pr上这样好不？

[nihui]

@nihui 这个translate版就先维持基于原滋原味的 glsl-extension.md 嘛🙈，至于qgroup所说的后面要补充的前置知识分享再分到其他pr上这样好不？

请把文中的 NCNN 改成 ncnn

[whyb]

@nihui 这个translate版就先维持基于原滋原味的 glsl-extension.md 嘛🙈，至于qgroup所说的后面要补充的前置知识分享再分到其他pr上这样好不？

请把文中的 NCNN 改成 ncnn

Edited

[nihui]

Thanks for your contribution !