Misleading error message in logical decoding for binary plugins

Hi all,

Using a plugin producing binary output, I came across this error:
=# select data from pg_logical_slot_peek_changes('foo', NULL, NULL);
ERROR: 0A000: output plugin cannot produce binary output
LOCATION: pg_logical_slot_get_changes_guts, logicalfuncs.c:404

Shouldn't the error message be here something like "binary output plugin
cannot produce textual output"? The plugin used in my case produces binary
output, but what is requested from it with pg_logical_slot_peek_changes is
textual output.

A patch is attached (with s/pluggin/plugin in bonus). Comments welcome.
Regards,
--
Michael