Add French subdivision aliases

[bors-ltd]

Proposed change

I had to look up in the source code what MQ, RE... meant. The README didn't help either, just listing the raw codes available.

Those are not of common use in the French culture, contrary to say, AZ meaning Arizona in the US culture.

Also fixed the official spelling.

Type of change

• New country/market holidays support (thank you!)
• Supported country/market holidays update (calendar discrepancy fix, localization)
• Existing code/documentation/test/process quality improvement (best practice, cleanup, refactoring, optimization)
• Dependency update (version deprecation/pin/upgrade)
• Bugfix (non-breaking change which fixes an issue)
• Breaking change (a code change causing existing functionality to break)
• New feature (new holidays functionality in general)

Checklist

• I've followed the contributing guidelines
• I've successfully run make check, all checks and tests are green

## Additional notes

For the record, it started with me adding a holiday calendar in my Home Assistant. I was left puzzled with that list:

And when I couldn't find the meaning of those abbreviations in the documentation either, I thought it was time to contribute.

The next step is to get in touch with the maintainers of this Home Assistant integration, and ask them to use the list of subdivision aliases when available.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (c13eed0) to head (5362815).
Report is 1 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff            @@
##               dev     #2162   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          194       194           
  Lines        11540     11541    +1     
  Branches      1641      1641           
=========================================
+ Hits         11540     11541    +1     

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[PPsyrius]

LGTM 🇫🇷

[sonarqubecloud]

Quality Gate passed

Issues
3 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[bors-ltd]

Sorry, I updated my PR after your review to write "La Réunion" everywhere for consistency.

That was also an opportunity to rebase on the upstream branch.

[KJhellico]

LGTM.

[arkid15r]

FR subdivs are still somewhat inconsistent with ISO 3166 but for v0 it's fine.

Thank you for adding this @bors-ltd

[arkid15r]

@bors-ltd FYI we started requiring signed commits this month however it's not checked on pre-commit or CI/CD so I'm accepting this one as is. Please look into setting this up if you're planning to contribute to holidays in future.

Thank you!

[bors-ltd]

Thanks, I'll have a look at ISO 3166, and find out how to sign my commit if I have something to iterate on.