✨ Generate automatic language names for docs translations

[jakul]

This PR does two things:

1. Update the code that generates the mkdocs.yml files to always include a local language name

   The local language name is read from a new file which contains mappings for all the allocated ISO 639-1 language codes, and the content of that file is sourced from https://quickref.me/iso-639-1, though with updates to persist the existing language names where there was a difference with the existing name for the language in the FastAPI source.

   ⚠️ The old code always put English at the top of the language list in the UI, but the new code doesn't

   Before	After

2. Regenerate all the mkdocs.yaml files

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (cf73051) 100.00% compared to head (9a1e1d0) 100.00%.
Report is 951 commits behind head on master.

❗ Current head 9a1e1d0 differs from pull request most recent head f35dcc5. Consider uploading reports for the commit f35dcc5 to get more accurate results

Additional details and impacted files

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  Coverage   100.00%   100.00%           
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  Files          540       539    -1     
  Lines        13969     13906   -63     
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- Hits         13969     13906   -63     

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[github-actions]

📝 Docs preview for commit 08870c6 at: https://63173af067cd57620b0f776e--fastapi.netlify.app

[MrRawbin]

Very cool! Good job.

[jakul]

Very cool! Good job.

Thanks for the quick response!

[github-actions]

📝 Docs preview for commit c485045 at: https://63177291e5cb61009f26b0ae--fastapi.netlify.app

[jakul]

Thanks for the review @BilalAlpaslan.

I noticed that the link to go back to the English version was wrong, it was /en/ instead of /. I've fixed that in a new commit.

[github-actions]

📝 Docs preview for commit 9a1e1d0 at: https://6318879624607c39852e219f--fastapi.netlify.app

[github-actions]

📝 Docs preview for commit a58f46b at: https://639cce20a7d043140d04044c--fastapi.netlify.app

[Xewus]

Honestly, if not for you, I would not have known about switching the language at the top of the page. 🤭

[bharathkalyans]

Actually, I was about to raise a PR regarding this issue, but found your PR that hasn't been yet merged 🥲.
Also, we have a new emoji language and I think shifting it below would give a better experience. Your take on this?

[creyD]

Thank you for this PR, looks good.

[tiangolo]

📝 Docs preview for commit 5b1d076 at: https://7e140f4b.fastapitiangolo.pages.dev

[tiangolo]

Great idea, thank you @jakul! This looks great. 🚀

And thanks for the reviews @creyD, @BilalAlpaslan, @MrRawbin, @Xewus, @alejsdev 🍰

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I updated docs.py with the recent changes and language setup refactor to use this data, and I updated the file to be YAML instead of JSON, just because all the other config files are YAML too, so, just for consistency. 😅