Revert move installation/upgrade-from-gogs.md in 1.21 (#28235)

https://github.com/go-gitea/gitea/pull/28233#discussion_r1405539630

docs/content/help/faq.en-us.md

@@ -39,6 +39,7 @@ If a bug fix is targeted on 1.20.1 but 1.20.1 is not released yet, you can get t
 
 To migrate from Gogs to Gitea:
 
+- [Gogs version 0.9.146 or less](installation/upgrade-from-gogs.md)
 - [Gogs version 0.11.46.0418](https://github.com/go-gitea/gitea/issues/4286)
 
 To migrate from GitHub to Gitea, you can use Gitea's built-in migration form.

docs/content/help/faq.zh-cn.md

@@ -41,6 +41,7 @@ menu:
 
 要从Gogs迁移到Gitea：
 
+- [Gogs版本0.9.146或更低](installation/upgrade-from-gogs.md)
 - [Gogs版本0.11.46.0418](https://github.com/go-gitea/gitea/issues/4286)
 
 要从GitHub迁移到Gitea，您可以使用Gitea内置的迁移表单。