RFR: 8354320: Changes to jpackage.md cause pandoc warning

[Alexey Semenyuk]

Escape the dollar sign.

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Commit messages:
 - 8354320: Changes to jpackage.md cause pandoc warning

Changes: https://git.openjdk.org/jdk/pull/24585/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24585&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8354320
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/24585.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24585/head:pull/24585

PR: https://git.openjdk.org/jdk/pull/24585