[9] Review request: 8170701: Update FXML documentation for setAccessible

[Kevin Rushforth]

Please review the following to update the FXML docs to document the 
requirement for a module that annotates non-public members with @FXML to 
"open" the containing package to the javafx.fxml module.

https://bugs.openjdk.java.net/browse/JDK-8170701
http://cr.openjdk.java.net/~kcr/8170701/webrev.00/
-- Kevin