pgsql: Improve tab-completion of DROP and ALTER ENABLE/DISABLE on trigg

Improve tab-completion of DROP and ALTER ENABLE/DISABLE on triggers and rules.

At "DROP RULE/TRIGGER triggername ON ...", tab-complete tables that have
a rule/trigger with that name.

At "ALTER TABLE tablename ENABLE/DISABLE TRIGGER/RULE ...", tab-complete to
rules/triggers on that table. Previously, we would tab-complete to all
rules or triggers, not just those that are on that table.

Also, filter out internal RI triggers from the list. You can't DROP them,
and enabling/disabling them is such a rare (and dangerous) operation that
it seems better to hide them.

Andreas Karlsson, reviewed by Ian Barwick.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/631e7f6b4e0629077408d3f8caf282627765f3f0

Modified Files
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src/bin/psql/tab-complete.c | 114 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 113 insertions(+), 1 deletion(-)