RFR: Fix link in RN-NewFeature to point to a publicly visible bug.

[Stuart Marks]

The old bug linked from this section (JDK-8193026) isn't publicly visible, which isn't very useful. Found by Tagir Valeev when he followed this procedure to write a release note.

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Commit messages:
 - Fix link in RN-NewFeature to point to a publicly visible bug.

Changes: https://git.openjdk.org/guide/pull/116/files
 Webrev: https://webrevs.openjdk.org/?repo=guide&pr=116&range=00
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/guide/pull/116.diff
  Fetch: git fetch https://git.openjdk.org/guide.git pull/116/head:pull/116

PR: https://git.openjdk.org/guide/pull/116