fix (typo): Corrected spelling of 'environments'

[BioGeek]

I changed environemnts to environments and added the tests folder to the spellcheck GitHub workflow and the Justfile so that that typos in this folder can also be caught in the future.

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📚 Documentation preview 📚: https://datasette--2268.org.readthedocs.build/en/2268/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (5d79974) 92.59% compared to head (d3a1238) 92.87%.
Report is 20 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2268      +/-   ##
==========================================
+ Coverage   92.59%   92.87%   +0.28%     
==========================================
  Files          42       41       -1     
  Lines        6348     6304      -44     
==========================================
- Hits         5878     5855      -23     
+ Misses        470      449      -21     

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[simonw]

Thanks for this - I appreciate the updates to the Justfile and CI.