bsdgrep: add -z/--null-data support and update NLS catalogs accordingly

MFC r317049: bsdgrep: add -z/--null-data support

-z treats input and output data as sequences of lines terminated by a
zero byte instead of a newline. This brings it more in line with GNU grep
and brings us closer to passing the current tests with BSD grep.

MFC r317679: bsdgrep: correct nls usage data after r317049

r317049 added -z/--null-data to BSD grep but missed the update to nls
catalogs.

Approved by: emaste (mentor, blanket MFC)
Relnotes: yes