runtime: document that SetCgoTraceback silently does nothing on non-linux/amd64 #24518
Description
Based on my read of the source code, runtime.SetCgoTraceback is only supported on linux/amd64. Ideally it would fail loudly if called on an unsupported platform, but just documenting the limitation would be a step forward. (At least, I don't see this documented anywhere.)
/cc @ianlancetaylor