According to a Gallup poll conducted last month, 61 percent of Americans are in favor of the death penalty for those convicted of murder. Only 35 percent are not. It wouldn’t surprise me to see that approval rating rise after the release of the documentary “Into the Abyss.” Which is a strange thing to say, since the man who made it firmly disapproves of capital punishment. But Werner Herzog never fails to surprise. Here, he explores a contentious topic that makes its way to the top of American consciousness with regularity — usually when a high-profile prisoner is set to be executed.