maint: --help now outputs bug reporting address

maint: --help now outputs bug reporting address

This changes the tail of "cat --help" output from:

GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/cat>
or available locally via: info '(coreutils) cat invocation'

to:

Report bugs to: bug-coreutils@gnu.org
GNU coreutils home page: <https://www.gnu.org/software/coreutils/>
General help using GNU software: <https://www.gnu.org/gethelp/>
Full documentation <https://www.gnu.org/software/coreutils/cat>
or available locally via: info '(coreutils) cat invocation'

* src/system.h (emit_bug_reporting_address): Don’t #define.
(emit_ancillary_info): Call emit_bug_reporting_address
instead of doing it by hand, which omitted the bug reporting address.