Assorted message improvements

src/backend/commands/view.c

src/backend/port/sysv_shmem.c

src/backend/rewrite/rewriteHandler.c

src/backend/utils/misc/guc.c

src/bin/pg_ctl/nls.mk

src/bin/psql/command.c

src/bin/psql/copy.c

src/test/regress/expected/updatable_views.out