The images used by Gitea's drone pipeline were upgraded to Go 1.19.x
It causes the lint fails because Go 1.19 uses new code format.
This PR partially backport #20758 (including the emoji-data sync),
partially fix the format manually.
Follows: #19284
* The `CopyDir` is only used inside test code
* Rewrite `ToSnakeCase` with more test cases
* The `RedisCacher` only put strings into cache, here we use internal `toStr` to replace the legacy `ToStr`
* The `UniqueQueue` can use string as ID directly, no need to call `ToStr`