Add “Register elsewhere” anywhere there is a “Register” button

So people are not forced to create an account on the same host.

If I currently go to https://timbl.com/timbl/, there is a "Register" button. This button leads me to register on timbl.com (which, BTW, isn't possible in the first place because this is a single-user instance). We should probably not force people to create an account on the first host they happen to access; rather, "Register" should explain that they have a choice.

首先跟踪 https://timbl.com/timbl/ 上显示的“Register”按钮，并找到其他 Register 按钮共享的代码。检查注册如何在各个 host 之间进行选择，然后确认每个 Register 入口点都会说明可用的选项，而不会强制在当前 host 上注册。