RFR: 8331077 : nroff man page update for jar tool

[Weibing Xiao]

nroff man page update for jar tool. <br>

This update is caused by the change of https://bugs.openjdk.org/browse/JDK-8318971. While the .md man pages got updated in other repos, the corresponding nroff man page was never updated in OpenJDK repos

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Commit messages:
 - 8331077 : nroff man page update for jar tool

Changes: https://git.openjdk.org/jdk/pull/19034/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19034&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8331077
  Stats: 6 lines in 1 file changed: 3 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/19034.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19034/head:pull/19034

PR: https://git.openjdk.org/jdk/pull/19034