fix: three character date time format code

[kaos]

✈️ Pre-flight checklist

• I have read the Contributing Guidelines on pull requests.
• If this is a code change: I have written unit tests and/or added dogfooding pages to fully verify the new behavior.
• [-] If this is a new API or substantial change: the PR has an accompanying issue (closes #0000) and the maintainers have approved on my working plan.

📝 Summary

Trying to use the %:z format code resulted in a ValueError.

🔥 Motivation

This PR adds a test showing the issue, along with implementation to fix it.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74%. Comparing base (ebd1555) to head (ba5eb8f).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@         Coverage Diff          @@
##           main   #1681   +/-   ##
====================================
  Coverage    74%     74%           
====================================
  Files        36      36           
  Lines      4079    4082    +3     
====================================
+ Hits       3052    3055    +3     
  Misses     1027    1027           

Flag	Coverage Δ
examples	36% <50%> (-1%)	⬇️
tests	74% <100%> (+<1%)	⬆️

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