The detailed description of shell job control (particularly, for the format, in which job IDs are specified) has been missed for years.
I adopted the POSIX standard text, describing shell job control (https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_203), tried to make it more easy-to-read and also made some small changes according to the actual sh(1) implementation in FreeBSD (e.g., it reports suspended status as 'Suspended', rather than 'Stopped').
I'm not very experienced with mdoc(7) and this is my first more-or-less big patch, so I will be very happy if you point out my mistakes.
PR: 206284