Reword 0034-use-citation-key-for-grouping-chat-messages.md

[koppor]

Some small rewordings.

Mandatory checks

• I own the copyright of the code submitted and I licence it under the MIT license
• Change in CHANGELOG.md described in a way that is understandable for the average user (if change is visible to the user)
• Tests created for changes (if applicable)
• Manually tested changed features in running JabRef (always required)
• Screenshots added in PR description (for UI changes)
• Checked developer's documentation: Is the information available and up to date? If not, I outlined it in this pull request.
• Checked documentation: Is the information available and up to date? If not, I created an issue at https://github.com/JabRef/user-documentation/issues or, even better, I submitted a pull request to the documentation repository.

[github-actions]

The build of this PR is available at https://builds.jabref.org/pull/12183/merge.

[InAnYan]

Oh no, what have I done 😆 . And this will be recorded in the Git history.

Thanks, Oliver, this ADR should definitely be reworded