feat: Expose identifiers in messages for no-duplicate-definitions

[juhwano]

Prerequisites checklist

• I have read the contributing guidelines.

What is the purpose of this pull request?

This pull request updates the no-duplicate-definitions rule to include the specific identifier in its error messages. This change helps developers quickly locate the specific definition causing the issue.

What changes did you make? (Give an overview)

• Updated the meta.messages of no-duplicate-definitions to include the {{ identifier }} placeholder.
• Updated the create function in the rule to pass the identifier through the data property in context.report().
• Updated the tests for the rule to verify that the identifier is correctly passed in invalid cases.

Related Issues

fixes #499

Is there anything you'd like reviewers to focus on?

[lumirlumir]

LGTM, thanks!

Would like another review before merging, since it's a small change but adds a new feature.

[lumirlumir]

To the team: I think using backticks here would be fine, since the similar rule no-unused-definition uses backticks as well.

markdown/src/rules/no-unused-definitions.js

Line 43 in 71e921a

"Unexpected unused footnote definition `{{ identifier }}` found.",

[nzakas]

LGTM. Thanks.

[injae-kim]

Awesome work @juhwano 🎉 🎉 🎉