update doc string to match signature (#4870)

py/server/deephaven/table_factory.py

@@ -63,7 +63,7 @@ def time_table(period: Union[Duration, int, str, datetime.timedelta, np.timedelt
  period (Union[dtypes.Duration, int, str, datetime.timedelta, np.timedelta64, pd.Timedelta]):
  time interval between new row additions, can be expressed as an integer in nanoseconds,
  a time interval string, e.g. "PT00:00:00.001" or "PT1s", or other time duration types.
- start_time (Union[None, str, datetime.datetime, np.datetime64], optional):
+ start_time (Union[None, Instant, int, str, datetime.datetime, np.datetime64, pd.Timestamp], optional):
  start time for adding new rows, defaults to None which means use the current time
  as the start time.
  blink_table (bool, optional): if the time table should be a blink table, defaults to False