fix: include required pull request template headings

[victorwon2001]

Fixes #3072

Summary

Preserve the approved implementation and update the submission metadata to match the pull request template requirements.

For reviewers

Please review the existing implementation and verification evidence.

Author attestation

• I have read and followed the contribution guidelines.

TODO

• None.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.71%. Comparing base (bd0dc84) to head (49f8c69).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4512   +/-   ##
=======================================
  Coverage   94.71%   94.71%           
=======================================
  Files          94       94           
  Lines       13663    13667    +4     
=======================================
+ Hits        12941    12945    +4     
  Misses        722      722           

Files with missing lines	Coverage Δ
src/zarr/core/array.py	98.44% <100.00%> (+<0.01%)	⬆️

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