RFR: 8330272: Fix javadocs for ValueLayout.(JAVA_LONG|JAVA_DOUBLE)

[Per Minborg]

This PR proposes to update the javadocs for `ValueLayout.JAVA_LONG` and `ValueLayout.JAVA_DOUBLE` to reflect the changes made in https://bugs.openjdk.org/browse/JDK-8326172  (we forgot to update the docs when that issue was fixed)

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Commit messages:
 - Update copyright year
 - Fix javadocs for ValueLayout.(JAVA_LONG|JAVA_DOUBLE)

Changes: https://git.openjdk.org/jdk/pull/18791/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18791&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8330272
  Stats: 5 lines in 1 file changed: 0 ins; 2 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/18791.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18791/head:pull/18791

PR: https://git.openjdk.org/jdk/pull/18791