corrections for echoing the last command when "!!" is given,

corrections for echoing the last command when "!!" is given,
undo working when 0 or 1 lines were in the buffer before the last buffer
modification, a RE interpretation correction; from Rodney Ruddock

SCCS-vsn: contrib/ed/bang.c 5.5
SCCS-vsn: contrib/ed/e.c 5.6
SCCS-vsn: contrib/ed/ed.h 5.6
SCCS-vsn: contrib/ed/edhup.c 5.4
SCCS-vsn: contrib/ed/f.c 5.4
SCCS-vsn: contrib/ed/filename.c 5.5
SCCS-vsn: contrib/ed/g.c 5.7
SCCS-vsn: contrib/ed/input_lines.c 5.9
SCCS-vsn: contrib/ed/main.c 5.8
SCCS-vsn: contrib/ed/q.c 5.6
SCCS-vsn: contrib/ed/r.c 5.7
SCCS-vsn: contrib/ed/re.c 5.4
SCCS-vsn: contrib/ed/sub.c 5.5
SCCS-vsn: contrib/ed/u.c 5.4
SCCS-vsn: contrib/ed/w.c 5.6