Include day and month abbreviations for Catalan

[NestorTejero]

Sources:

• https://www.ub.edu/cub/llistat_ab.php?taula=DS&ordre=mots_t&idioma=1
• https://aplicacions.llengua.gencat.cat/llc/AppJava/index.html?action=Principal&method=detall&input_cercar=abreviatures+mesos&numPagina=1&database=FITXES_PUB&idFont=8402&idHit=8402&tipusFont=Fitxes+de+l%2527Optimot&numeroResultat=1&databases_avansada=&categories_avansada=&clickLink=detall&titol=abreviatures+dels+mesos+de+l%2527any&tematica=&tipusCerca=cerca.normes

Pull Request Checklist

Thank you for taking the time to improve Arrow! Before submitting your pull request, please check all appropriate boxes:

• [ ] 🧪 Added tests for changed code.
• [ ] 🛠️ All tests pass when run locally (run tox or make test to find out!).
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• [ ] 📚 Updated documentation for changed code.
• [ ] ⏩ Code is up-to-date with the master branch.

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Description of Changes

[codecov[bot]]

Codecov Report

Merging #853 into master will not change coverage. The diff coverage is n/a.

@@            Coverage Diff            @@
##            master      #853   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
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  Files            9         9           
  Lines         1808      1808           
  Branches       312       312           
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  Hits          1808      1808           

Impacted Files	Coverage Δ
arrow/locales.py	100.00% <ø> (ø)

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[jadchaar]

Seems like the title casing is in fact intentional: https://wordinfo.info/unit/3230. Should be good to merge this once CI passes.

[NestorTejero]

Looks good, but was the removal of title casing intentional @NestorTejero?

yes! In Catalan, month and week day names are not capitalized (unless in the beginning of a sentence). I included the sources in my first comment. Thanks for cross checking.