[jdk11u-dev] RFR: 8290209: jcup.md missing additional text

[Goetz Lindenmaier]

I backport this for parity with 11.0.17-oracle.

-------------

Commit messages:
 - Backport 2bf6285c80f078d8451afb5682ee307bb13be179

Changes: https://git.openjdk.org/jdk11u-dev/pull/1360/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=1360&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290209
  Stats: 11 lines in 1 file changed: 9 ins; 2 del; 0 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1360.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev pull/1360/head:pull/1360

PR: https://git.openjdk.org/jdk11u-dev/pull/1360