Marking options deprecated in help output

In the pg_dump blob terminology thread it was briefly discussed [0] to mark
parameters as deprecated in the --help output.  The attached is a quick diff to
show that that would look like.  Personally I think it makes sense, not
everyone will read the docs.

--
Daniel Gustafsson		https://vmware.com/

[0] 95467596-834d-baa4-c67c-5db1096ed549@enterprisedb.com