Adjusted psql echoing options (-a and -e)

doc/src/sgml/ref/psql-ref.sgml

src/bin/psql/common.c

src/bin/psql/help.c

src/bin/psql/mainloop.c

src/bin/psql/startup.c

src/bin/psql/variables.c

src/bin/psql/variables.h

src/test/regress/regress.sh

src/test/regress/run_check.sh