RFR: 8354334: Remove @ValueBased from ProcessHandle

[Roger Riggs]

Remove internal ValueBased annotation from the ProcessHandle interface declaration.
The implementation remains value based as described in the javadoc. 
Remove unnecessary "public" keyword in interfaces and cleanup javadoc.

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Commit messages:
 - 8354334: Remove @ValueBased from ProcessHandle

Changes: https://git.openjdk.org/jdk/pull/24986/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24986&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8354334
  Stats: 16 lines in 1 file changed: 0 ins; 3 del; 13 mod
  Patch: https://git.openjdk.org/jdk/pull/24986.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24986/head:pull/24986

PR: https://git.openjdk.org/jdk/pull/24986