[Integrated] [foreign-jextract] RFR: 8242288: Sample code has to be adjusted after recent changes in jextract generated code

[Athijegannathan Sundararajan]

Changeset: 5dac84ab
Author:    Athijegannathan Sundararajan <sundar at openjdk.org>
Date:      2020-04-07 17:10:34 +0000
URL:       https://git.openjdk.java.net/panama-foreign/commit/5dac84ab

8242288: Sample code has to be adjusted after recent changes in jextract generated code

Reviewed-by: jvernee

! doc/panama_jextract.html
! doc/panama_jextract.md