[11] RFR JDK-8198777: JList.getPreferredScrollableViewportSize(): fix mistake in doc for height calc

[Alexey Ivanov]

Hello,

Could you please review the fix for jdk11?
bug: https://bugs.openjdk.java.net/browse/JDK-8198777
webrev: http://cr.openjdk.java.net/~aivanov/8198777/webrev.0/
csr: https://bugs.openjdk.java.net/browse/JDK-8198822

It is a small fix to documentation of 
JList.getPreferredScrollableViewportSize().

If either fixedCellWidth or fixedCellHeight are not set and the model 
isn't empty, heuristics are used. The height is based one the height of 
the first cell rather than fixedCellHeight.


Regards,
Alexey