[9] Review request: 8178281: Remove @link reference to Module class until boot JDK is updated

[Kevin Rushforth]

Phil,

Please review the following fix (which is a follow-on to JDK-8177751).
https://bugs.openjdk.java.net/browse/JDK-8178281

The patch is in the JBS; it changes "{@link Module#addOpens}" to {@code 
Module.addOpens} in one more place.

-- Kevin