Requested. See manpage additions.
The main reason why this goes through the trouble to keep the
action/operation parameter separate is so that we don't expose some
option parser implementation details to the command (although that is a
relatively weak reason), and also to make it more different from the
"set" command, which can't support this type of option as it goes
through the property layer.
Fixes#5435.
wm4
0d359879c9