Some message fixes

Hello.

While translating message catalogs, I found that some messages
listing object names are missing partitioned tables/indices.
And GUC comment for autovacuum_work_mem has a typo.

1. some messages are missing partitioned table/index

The first attached. I'm not sure how the orering ought to be
but I arranged them in mainly in the appearance order in if()
conditions, or the order of case label in switch()
construct. One exception is ATExecChangeOwner, in which the
order is the others regardless of the case label order just
above.

This is backpatchable to 10 but 10 doesn't have partitioned
index so needs a different fix (Second attached).

# But, I'm not sure if the list may be that long...

2. GUC comment for autovacuum_work_mem has a typo, "max num of
parallel workers *than* can be..". (Third attached)

regards,

--
Kyotaro Horiguchi
NTT Open Source Software Center