Can you show me where this right to death is listed? Because I can show you right to life in a bunch of international human rights documents, and from there in a bunch of law in different countries.
As I put it, I really think it is implicit in the right to life. The right to life means you should have the control over your life/death. You don't really have a right to life if you don't control the most basic part of that, life itself.
Very few countries give people a right to death.