Remove unnecessary code and fix comments (#35761)

Follow #35459, #32562

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

routers/web/repo/setting/setting.go

@@ -207,11 +207,6 @@ func handleSettingsPostUpdate(ctx *context.Context) {
 	repo.Website = form.Website
 	repo.IsTemplate = form.Template
 
-	// Visibility of forked repository is forced sync with base repository.
-	if repo.IsFork {
-		form.Private = repo.BaseRepo.IsPrivate || repo.BaseRepo.Owner.Visibility == structs.VisibleTypePrivate
-	}
-
 	if err := repo_service.UpdateRepository(ctx, repo, false); err != nil {
 		ctx.ServerError("UpdateRepository", err)
 		return