out-of-date comment in CreateRestartPoint()

This comment obviously requires adjustment now that HS is committed.
The obvious way to change it is to replace "when we get hot standby
capability" with "when running in Hot Standby mode", but I'm not clear
whether that's all that's required.

/*
* If the last checkpoint record we've replayed is already our last
* restartpoint, we can't perform a new restart point. We still update
* minRecoveryPoint in that case, so that if this is a shutdown restart
* point, we won't start up earlier than before. That's not strictly
* necessary, but when we get hot standby capability, it would be rather
* weird if the database opened up for read-only connections at a
* point-in-time before the last shutdown. Such time travel is still
* possible in case of immediate shutdown, though.
*
* We don't explicitly advance minRecoveryPoint when we do create a
* restartpoint. It's assumed that flushing the buffers will
do that as a
* side-effect.
*/

Thoughts?

--
Robert Haas
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