For a few commands the options aren't fully documented. This commit
makes the manpage documentation (almost) match the options shown
when you run "<command> --help" on the command line.
(cherry picked from commit 2d07f7d455)
This adds --forbid-read, --forbid-write, --forbid-delete and
--forbid-grant-permissons options to flatpaks document-export
command, to let it revoke permissions on exported documents.