Following commit be1f7435ef218b1d ("kern: start tracking cr_gid outside
of cr_groups[]"), cr_groups[] doesn't contain the effective GID anymore.
Fix the 'show proc' DDB command to show it again, and make it stand out
with respect to the supplementary ones.
Fixes: be1f7435ef218b1d ("kern: start tracking cr_gid outside of cr_groups[]")
Sponsored by: The FreeBSD Foundation