建议为 nz-icon 提供类似 signal-queries-migration 更友好的迁移命令

[cipchk]

很多情况下并不是通过 ng update 来升级的，特别是一些带有工作空间的情况下；个人觉得可以考虑增加类似：

ng generate ng-zorro-antd:nz-icon-element

作为已经是 Angular 19+ 项目的情况下，这样的命令还是非常有意义的。

[zorro-bot]

Translation of this issue:

Suggestion provides a more friendly migration command for nz-ICon

In many cases, it is not upgraded by ng update, especially when there are some work space; I personally think that it can be considered to add similar:

` ng generate ng-zorro -Ntd: icon-migration `

In the case of the Angular 19+ project, such a command is still very meaningful.

[Laffery]

@cipchk 在 HTML 中将 i[nz-icon] span[nz-icon] 迁移至 nz-icon 是不难的。
但对于 CSS 中的选择器，尤其是通过 ::ng-deep 覆写的样式，若被覆写组件为三方组件（非开发者项目中的组件/zorro组件），无法保证三方组件模板已经是 nz-icon，因此我们无法为开发者统一迁移。WDYT？