RFR: 2150: Allow pull requests to have the title "Merge"

Thu Jan 18 13:21:59 UTC 2024

Hi all,

please review this patch that allow "merge style" pull requests to have just the title "Merge". If the title is just "Merge" then the bots will rewrite the title to `Merge <HEAD>` where `<HEAD>` is the HEAD of the pull request source branch. This is useful if the integrator knows that they want the HEAD of the pull request source branch as the second parent for the resulting merge commit (this removes the need to manually specify the HEAD hash in the PR title).

### Testing
- [x] Added a new unit test

Thanks,
Erik

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Commit messages:
 - Fix whitespace
 - 2150

Changes: https://git.openjdk.org/skara/pull/1602/files
 Webrev: https://webrevs.openjdk.org/?repo=skara&pr=1602&range=00
  Issue: https://bugs.openjdk.org/browse/SKARA-2150
  Stats: 70 lines in 2 files changed: 70 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/skara/pull/1602.diff
  Fetch: git fetch https://git.openjdk.org/skara.git pull/1602/head:pull/1602

PR: https://git.openjdk.org/skara/pull/1602