File psl-1983/3-1/doc/nmode/nm-mark.contents artifact f2f75e6698 part of check-in ed4c581dbb

contents_entry(0 10 {The Mark and the Region} 10-1)
contents_entry(1 10.1 {Commands to Mark Textual Objects} 10-2)
contents_entry(1 10.2 {The Ring of Marks} 10-2)