Add getComment() to ChangeLogSet.Entry

[0xShubhamSolanki]

Fixes #22542

Adds a new getComment() method to ChangeLogSet.Entry to expose the full commit message.

Currently, only getMsg() is available, which typically returns the short commit message.
Some integrations and API consumers require access to the full commit message.

The default implementation of getComment() returns getMsg() to preserve backward compatibility and existing behavior.
SCM implementations may override this method if they provide a distinct full commit message.

Testing done

Built Jenkins core locally with JDK 21.

mvn -pl core clean verify

Added automated unit test ChangeLogSetEntryTest which verifies:

• getComment() returns the same value as getMsg() by default.
• getComment() can be overridden by concrete SCM implementations.

The test includes a concrete anonymous subclass of ChangeLogSet.Entry to simulate real SCM implementations overriding the method.

Confirmed that:

• No existing behavior was modified.
• No UI behavior was changed.
• getMsgAnnotated() continues to work as expected.
• Build, Checkstyle, Spotless, and SpotBugs all pass.

Screenshots (UI changes only)

Before

N/A

After

N/A

Proposed changelog entries

• Expose full commit message via getComment() in ChangeLogSet.Entry.

Proposed changelog category

/label developer

Proposed upgrade guidelines

N/A

Submitter checklist

• The issue, if it exists, is well-described.
• The changelog entries and upgrade guidelines are appropriate.
• There is automated testing.
• The new public method is annotated with @Exported and @since 2.552.
• No UI or dependency changes were introduced.
• For the new API method, there is at least one consumer (unit test simulating SCM override).

Desired reviewers

@MarkEWaite

[MarkEWaite]

I've converted the pull request to draft because you've made several mistakes that need to be corrected before anyone reviews the pull requests. Those mistakes include:

• Did not complete the full pull request template. Restore the pull request template and complete it, including a detailed description of how you interactively confirmed the new functionality is working
• Did not provide tests for the newly added method
• Did not provide at least one implementation that uses the newly added method
• Made unrelated and unnecessary changes in the pull request. Reduce the pull request to its minimum impact. Remove the unnecessary and unrelated changes

If those steps are not taken promptly, I'll close the pull request as wasting maintainer time. In the future, pull requests like this will one will be immediately closed.

[MarkEWaite]

Requesting changes based on my previous comment

[0xShubhamSolanki]

Thank you for the detailed feedback.
I will update the PR to include proper tests, restore the template, remove unrelated changes, and provide at least one usage example of the new method.

[0xShubhamSolanki]

@MarkEWaite
I have addressed the requested changes, restored the PR template, removed unrelated changes, added proper tests and usage example, and rebased the branch.
Kindly let me know if any further changes are required.

[MarkEWaite]

@MarkEWaite I have addressed the requested changes, restored the PR template, removed unrelated changes, added proper tests and usage example, and rebased the branch. Kindly let me know if any further changes are required.

Thanks. I will be on vacation for the next two weeks, so won't be reviewing pull requests in any significant way. I'll review this after I return from vacation.