RFR: 8359248: JFR: Help text for-XX:StartFlightRecording:report-on-exit should explain option can be repeated

[Erik Gahlin]

Could I have review of a PR that updates the help text for report-on-exit so it clarifies that the option can be repeated.

Testing: jdk/jdk/jfr + tier1

Thanks
Erik

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Commit messages:
 - Initial

Changes: https://git.openjdk.org/jdk/pull/25797/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25797&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8359248
  Stats: 9 lines in 2 files changed: 3 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/25797.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25797/head:pull/25797

PR: https://git.openjdk.org/jdk/pull/25797