[Sweep Rules] Add unit tests for new methods in FormatInformation and Writer classes

[ ] 👍 Sweep Did Well
[ ] 👎 Sweep Needs Improvement

I created this PR to address this rule:

"All new business logic should have corresponding unit tests."

Description

This PR adds unit tests for the new methods in the FormatInformation and Writer classes. The following changes were made:
Created a new unit test file FormatInformationTest.php in the tests directory to test the addFormatInformation method in the FormatInformation class.
Modified the existing WriterTest.php file in the tests directory to include unit tests for the convertHead, convertSubms, convertSours, convertIndis, convertFams, convertNotes, convertRepos, and convertObjes methods in the Writer class.

Summary of Changes

Created tests/FormatInformationTest.php to test the addFormatInformation method in the FormatInformation class.
Modified tests/WriterTest.php to include unit tests for the convertHead, convertSubms, convertSours, convertIndis, convertFams, convertNotes, convertRepos, and convertObjes methods in the Writer class.

Please review and merge these changes.