RFR: 8174840: Elements.overrides does not check the return type of the methods

[Pavel Rappo]

Please review this essentially doc only change.

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Commit messages:
 - Fix copy-paste issues
 - Initial commit

Changes: https://git.openjdk.org/jdk/pull/22244/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22244&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8174840
  Stats: 90 lines in 6 files changed: 78 ins; 4 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/22244.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22244/head:pull/22244

PR: https://git.openjdk.org/jdk/pull/22244