TG_RELNAME was marked deprecated in commit 3a9ae3d2068 some 14 years ago, but
we still use it in the triggers test suite (test added in 59b4cef1eb74a a year
before deprecation). Seems about time to move over to TG_TABLE_NAME ourselves,
as TG_RELNAME is still covered by the test added in the deprecation commit.
cheers ./daniel