RFR: 8319450: Add missing @since tags for new ofLiteral() methods

[Marc R. Hoffmann]

8319450: Add missing @since tags for new ofLiteral() methods

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Commit messages:
 - 8319450: Add missing @since tags for new ofLiteral() methods

Changes: https://git.openjdk.org/jdk/pull/16510/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16510&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8319450
  Stats: 3 lines in 3 files changed: 3 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/16510.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16510/head:pull/16510

PR: https://git.openjdk.org/jdk/pull/16510