RFR: pr: fix Markdown for /backport

[Erik Helin]

Hi all,

please review this small patch that fixes the Markdown in the pull request created by the `/backport` commit command. I had simply forgotten to call `.get()` on an `Optinal<String>` �� 

Thanks,
Erik

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Commit messages:
 - pr: fix Markdown for /backport

Changes: https://git.openjdk.java.net/skara/pull/1018/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=1018&range=00
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/skara/pull/1018.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1018/head:pull/1018

PR: https://git.openjdk.java.net/skara/pull/1018