Remove comments - don't work on forks

[koppor]

I thought it would be nice to have some messages at PRs when sth goes wrong.

However, only persons with access rights to this repo get these texts - others not.

Thus, I remove them.

@reviewdog can. Follow-up is to convert the output in case of errors to a format consumable to reviewdog.

Mandatory checks

• Change in CHANGELOG.md described in a way that is understandable for the average user (if applicable)
• 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]

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