RFR: 8267329: Modernize Javadoc code to use instanceof with pattern matching

[Ian Graves]

8267329: Modernize Javadoc code to use instanceof with pattern matching

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Commit messages:
 - Updating javadoc to use instanceof patterns

Changes: https://git.openjdk.java.net/jdk/pull/4105/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4105&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8267329
  Stats: 85 lines in 25 files changed: 0 ins; 11 del; 74 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4105.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4105/head:pull/4105

PR: https://git.openjdk.java.net/jdk/pull/4105