File psl-1983/3-1/doc/nmode/nm-subsystems.topic from the latest check-in

.silent_index {Recursive} idx 7-1
.silent_index {Mode} idx 7-1
.silent_index {stop} idx 7-2
.silent_index {C-X} idx 7-2
.silent_index {C-} idx 7-2
.silent_index {exiting} idx 7-2