Extend the description of the Persist Service

Under "ORDERED", there are the following two sentences:

By definition, PERSIST on an attribute means the attribute is evaluated outside of any given evaluation order. Therefore, ORDERED has no effect on PERSISTed attributes.

The second sentence is correct, but not because of the first sentence.

It would be clearer to have:

ORDERED has no effect on PERSISTed attributes.

The first sentence could be moved to the Persist page, where it would provide useful information about the nature of PERSISTs.

However, it should also be clarified, so that it doesn't incorrectly describe SEQUENTIAL statements.

Maybe, a description like the following could be at the end of the "PERSIST" page:

Persisted attributes can still be subject to the ordering requirements of SEQUENTIAL. However, since persists are shared between workunits, there is no guarantee that the attribute will be evaluated within any given evaluation order. 

This gives more information about how persists work