man/cli: better explain modifying properties regarding +/- modifiers

16 jobs for th/cli-modify-enums-and-cleanup in 32 minutes and 57 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed #499916
allowed to fail
checkpatch

00:01:01

manual #499921
allowed to fail manual
t_centos:7.5.1804
passed #499922
t_centos:7.6.1810

00:27:03

passed #499928
t_debian:10

00:16:46

passed #499927
t_debian:9

00:15:25

passed #499930
t_debian:sid

00:16:38

manual #499929
allowed to fail manual
t_debian:testing
passed #499917
t_fedora:28

00:25:20

passed #499918
t_fedora:29

00:32:54

passed #499919
t_fedora:30

00:25:44

manual #499920
allowed to fail manual
t_fedora:rawhide
passed #499923
t_ubuntu:16.04

00:20:59

passed #499924
t_ubuntu:18.04

00:15:24

manual #499926
allowed to fail manual
t_ubuntu:devel
manual #499925
allowed to fail manual
t_ubuntu:rolling
 
  External
passed default