trap stack: execute POSIX trap after stack traps, not before
trap stack: execute POSIX trap after stack traps, not before

On second thought, execute the POSIX trap (if any) after the stack traps
(if any), because the former are commonly programmed to exit the shell.
This does mean POSIX traps cannot rely on modernish functionality that
cleans up after itself using the trap stack.

modernish/modernish