Document "supervisorctl avail" action

[whereisaaron]

supervisorctl has an action avail that's not mentioned in the documentation at
http://supervisord.org/running.html#supervisorctl-actions

Not sure what it does. Output looks like below but with no column headings, not clear what it means?

$ supervisorctl avail
apache                           in use    auto      999:999
log                              in use    auto      -1:999
queue:queue0                     in use    auto      999:999

CLI documentation just said "Display all configured processes", but not clear what about those processes is being displayed?

> help avail
avail                   Display all configured processes

[jamespo]

From a very quick play the "in use" column changes to "avail" if you remove a process group. manual/auto speak for themselves. Unsure what the numeric range represents however.