Draft JEP: Derived Record Creation (Preview)

[Gavin Bierman]

Dear Spec Experts,

We have discussed on this list a new `with` expression form to derive new record
values from existing record values. A draft JEP for this feature is now
available:

https://bugs.openjdk.org/browse/JDK-8321133

Please take a look at this new JEP and give us your feedback (either on this
list or directly to me).

Thanks,
Gavin