pgsql: Update psql startup banner to be shorter, suggest "help" for

Log Message:
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Update psql startup banner to be shorter, suggest "help" for help.

Add a few "help" entries.

Move \g help entry into "General".

Update psql version mismatch warning text.

Joshua D. Drake

Modified Files:
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pgsql/doc/src/sgml:
start.sgml (r1.46 -> r1.47)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/start.sgml?r1=1.46&r2=1.47)
pgsql/doc/src/sgml/ref:
psql-ref.sgml (r1.205 -> r1.206)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/psql-ref.sgml?r1=1.205&r2=1.206)
pgsql/src/bin/psql:
help.c (r1.127 -> r1.128)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/help.c?r1=1.127&r2=1.128)
mainloop.c (r1.90 -> r1.91)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/mainloop.c?r1=1.90&r2=1.91)
startup.c (r1.147 -> r1.148)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/startup.c?r1=1.147&r2=1.148)