doc: reference online info pages directly from man pages

doc: reference online info pages directly from man pages

* src/system.h (emit_ancillary_info): Add a direct reference
to the corresponding online info documentation.  Corresponding
redirects were put in place on www.gnu.org to allow for concise links.
* help2man: Adjust to add the "online help" link (and subsequent
translation bugs link) to a "REPORTING BUGS" section.
Also add the concise links for further information in --help
to the "SEE ALSO" section, and dispense with the more verbose
default for that.