pgsql: Message and documentation refinements

Message and documentation refinements

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/660ee7bec276b69605b3c997ee740d5d386ad2c3

Modified Files
--------------
doc/src/sgml/protocol.sgml | 4 ++--
src/bin/psql/describe.c | 2 +-
src/test/regress/expected/subscription.out | 30 +++++++++++++++---------------
3 files changed, 18 insertions(+), 18 deletions(-)