Doc: document more incompatible pg_restore option pairs.

Doc: document more incompatible pg_restore option pairs.

Most of the pairs of incompatible options (such as --file and --dbname)
are pretty obvious and need no explanation.  But it may not be obvious
that --single-transaction cannot be used together with --create or
multiple jobs, so let's mention that in the documentation.

Author: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Laurenz Albe <laurenz.albe@cybertec.at>
Discussion: https://postgr.es/m/CAExHW5ti5igDwOOde6shgfS7JPtCY9gNrkB3xNr=FuGTYVDSjQ@mail.gmail.com