improve example cases for package gi18n

[hailaz]

gvalid的单测和示例混着部分隐式使用i18n的情况，而且这个i18n来自util/gvalid/i18n文件夹，不太规范。
现在移除util/gvalid/i18n文件夹使用util/gvalid/testdata/i18n中的数据，两个文件夹的内容基本重复。

[codecov-commenter]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.14% 🎉

Comparison is base (395df94) 79.09% compared to head (46f8ac7) 79.24%.

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Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2970      +/-   ##
==========================================
+ Coverage   79.09%   79.24%   +0.14%     
==========================================
  Files         643      643              
  Lines       52754    52754              
==========================================
+ Hits        41727    41806      +79     
+ Misses       8945     8867      -78     
+ Partials     2082     2081       -1     

Flag	Coverage Δ
go-1.18-386	79.27% <100.00%> (+0.10%)	⬆️
go-1.18-amd64	79.27% <100.00%> (+0.10%)	⬆️
go-1.19-386	79.21% <100.00%> (+0.14%)	⬆️
go-1.19-amd64	79.16% <100.00%> (+0.11%)	⬆️
go-1.20-386	79.33% <100.00%> (+0.28%)	⬆️
go-1.20-amd64	79.25% <100.00%> (+0.09%)	⬆️
go-1.21-386	79.23% <100.00%> (+0.08%)	⬆️
go-1.21-amd64	79.33% <100.00%> (+0.23%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
util/gvalid/internal/builtin/builtin_password.go	100.00% <100.00%> (+18.18%)	⬆️
util/gvalid/internal/builtin/builtin_password2.go	100.00% <100.00%> (+13.33%)	⬆️
util/gvalid/internal/builtin/builtin_password3.go	100.00% <100.00%> (+12.50%)	⬆️

... and 40 files with indirect coverage changes

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[gqcn]

@hailaz 单例和示例代码没必要严格解耦，特别是示例的代码是你的代码写什么样别人看到就是什么样，假如你做了封装了其实别人看示例代码会很懵的。比如：

[hailaz]

@hailaz 单例和示例代码没必要严格解耦，特别是示例的代码是你的代码写什么样别人看到就是什么样，假如你做了封装了其实别人看示例代码会很懵的。比如：

那就统一示例吧，现在是有些返回信息是指定了i18n的信息，有些返回了默认信息。然后这个i18n的目录文件其实和testdata中的i18n是重复的，而且本该放到testdata中。

[Issues-translate-bot]

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@hailaz There is no need to strictly decouple the singleton and the sample code. Especially the sample code is what others see when you write the code. If you encapsulate it, others will be confused when they see the sample code. For example:

Let’s unify the examples. Now some of the returned information specifies i18n information, and some return default information. Then this i18n directory file is actually duplicated with the i18n in testdata, and should have been placed in testdata.