Identical to `0=`, used for program clarity to reverse the
result of a previous test.
WARNING: PFE's NOT uses bitwise complement INVERT instead of the logical complement 0=, so
that loading TOOLBELT will change semantics.
... this difference in semantics has caused dpans94 to
depracate the word. Only if TRUE is -1 it would be identical
but not all words return -1 for true.