🔨 Replace polyfill.io in the docs and the site

[SukkaW]

The PR replaces the polyfill.io inside the docs and the site to cdnjs.cloudflare.com/polyfill.

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polyfill.io was acquired by a China-based CDN company "Funnull", see the announcement from the polyfill.io domain owner's Twitter and https://github.com/polyfillpolyfill/polyfill-service/issues/2834. Despite Funnull's claims of operating in the United States, the predominance of Simplified Chinese on its website suggests otherwise, and it turns out that "Funnull" is notorious for providing service for the betting and pornography industries.

The original creator of the polyfill.io has voiced his concern on Twitter. And since the acquisition, numerous issues have emerged (polyfillpolyfill/polyfill-service#2835, polyfillpolyfill/polyfill-service#2838, alist-org/alist#6100), rendering the polyfill.io service extremely unstable. Since then, Fastly (Announcement) and Cloudflare (Announcement) has hosted their own instances of polyfill.io service.

[shuuji3]

Also, three other repositories use polyfill.io under this org:
https://github.com/owid/owid-grapher-py
https://github.com/owid/owid.github.io
https://github.com/owid/owid-importer (already archived)

ref. https://github.com/search?q=org%3Aowid+polyfill.io&type=code

[marcelgerber]

Hi, and thank you for notifying us of this issue.
I'll quickly check how using Cloudflare for this compares performance-wise, but otherwise this is good to go.

[shuuji3]

Fastly is also providing alternative polyfill CDN (https://community.fastly.com/t/new-options-for-polyfill-io-users/2540). In case of any performance issues, you may evaluate it with Cloudflare as well.

[marcelgerber]

This works great, thank you again!

[larsyencken]

@SukkaW Given the recent supply chain attack using polyfill, we're especially grateful for this contribution of yours some months back. 🙇

https://sansec.io/research/polyfill-supply-chain-attack

[shuuji3]

Yes, @SukkaW did a great job for various GitHub repositories! 👍🏻