RFR: Fix links to #trivial-changes

[Manuel Hässig]

This simple PR fixes broken links to the "Trivial Changes" section.

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Commit messages:
 - Fix links to trivial-changes

Changes: https://git.openjdk.org/guide/pull/156/files
  Webrev: https://webrevs.openjdk.org/?repo=guide&pr=156&range=00
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/guide/pull/156.diff
  Fetch: git fetch https://git.openjdk.org/guide.git pull/156/head:pull/156

PR: https://git.openjdk.org/guide/pull/156