Add zim string.

[rtibbles]

Summary

Description of the change(s) you made

Adds a string "ZIM" for the "zim" kind.

References

Fixes #4205

Comments

I don't have any zim files imported locally to test this, but this seemed like a very straight forward fix.

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Contributor's Checklist

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• If this is an important user-facing change, PR or related issue the CHANGELOG label been added to this PR. Note: items with this label will be added to the CHANGELOG at a later time
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Studio-specifc:

• All user-facing strings are translated properly
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Reviewer's Checklist

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• Automated test coverage is satisfactory
• PR is fully functional
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• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
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