message: Add test for interval type description
diff: @@ -40,3 +40,13 @@ class TestPythonResult(object):
  rel = connection.table("timestamps")
  assert rel.execute().fetchall() == [(datetime.datetime(2008, 1, 1, 0, 0, 11), datetime.datetime(2008, 1, 1, 0, 0, 1, 794000), datetime.datetime(2008, 1, 1, 0, 0, 1, 989260), datetime.datetime(2008, 1, 1, 0, 0, 1, 899268))]
  + def test_result_interval(self):
  + connection = duckdb.connect()
  + cursor = connection.cursor()
  + cursor.execute('CREATE TABLE IF NOT EXISTS intervals (ivals INTERVAL)')
  + cursor.execute("INSERT INTO intervals VALUES ('1 day'), ('2 second'), ('1 microsecond')")
  +
  + rel = connection.table("intervals")
  + res = rel.execute()
  + assert res.description() == [('ivals', 'TIMEDELTA', None, None, None, None, None)]
  + assert res.fetchall() == [(datetime.timedelta(days=1.0),), (datetime.timedelta(seconds=2.0),), (datetime.timedelta(microseconds=1.0),)]
  