replace polyfill.io link, close #1350

Author: zloirock

docs/2023-02-14-so-whats-next.md

@@ -534,7 +534,7 @@ Lighthouse shows just about 200KB in all resources, 0.56s. Let's remember that t
 
 From the very beginning of work on `core-js`, I've been thinking about creating a web service that serves only the polyfills needed for the requesting browser.
 
-The availability of a such service is the only aspect in which `core-js` have lagged behind another project. [`polyfill-service`](https://polyfill.io) from Financial Times is based on this conception and it's a great service. The main problem with this project — it's a great service that uses poor polyfills. This project polyfills only a little part of the ECMAScript features that `core-js` provides, most of the polyfills are third-party and are not designed to work together, too many don't properly follow specs, too unpolished or just dangerous for usage (for example, [`WeakMap` looks like a step-by-step implementation of the spec text](https://github.com/Financial-Times/polyfill-library/blob/554248173eae7554ef0a7776549d2901f02a7d51/polyfills/WeakMap/polyfill.js), but the absence of some non-spec magic cause memory leaking and linear access time that makes it harmful, but here's more — instead of patching, fixing and reusing of native implementation in engines like IE11 where it's available, but does not accept an iterable argument, [`WeakMap` will be completely replaced](https://github.com/Financial-Times/polyfill-library/blob/554248173eae7554ef0a7776549d2901f02a7d51/polyfills/WeakMap/detect.js)). Some good developers try to fix this from time to time, but polyfills themselves are given unforgivably little time, so it's still too far from something that could be recommended for usage.
+The availability of a such service is the only aspect in which `core-js` have lagged behind another project. [`polyfill-service`](https://cdnjs.cloudflare.com/polyfill/) is based on this conception and it's a great service. The main problem with this project — it's a great service that uses poor polyfills. This project polyfills only a little part of the ECMAScript features that `core-js` provides, most of the polyfills are third-party and are not designed to work together, too many don't properly follow specs, too unpolished or just dangerous for usage (for example, [`WeakMap` looks like a step-by-step implementation of the spec text](https://github.com/Financial-Times/polyfill-library/blob/554248173eae7554ef0a7776549d2901f02a7d51/polyfills/WeakMap/polyfill.js), but the absence of some non-spec magic cause memory leaking and linear access time that makes it harmful, but here's more — instead of patching, fixing and reusing of native implementation in engines like IE11 where it's available, but does not accept an iterable argument, [`WeakMap` will be completely replaced](https://github.com/Financial-Times/polyfill-library/blob/554248173eae7554ef0a7776549d2901f02a7d51/polyfills/WeakMap/detect.js)). Some good developers try to fix this from time to time, but polyfills themselves are given unforgivably little time, so it's still too far from something that could be recommended for usage.
 
 Creating such a service in the proper form requires the creation and maintenance of many new components. I work on `core-js` alone, the project does not have the necessary support from any company, and the development is carried out with pure enthusiasm, I need to look for funds to feed myself and my family, so I have no time and other resources required for that. However, in the scope of other tasks, I already made some required components, and discussions with some users convinced me that creating a maximally simplified service that you could start on your own server could be enough.
 

docs/zh_CN/2023-02-14-so-whats-next.md

@@ -596,7 +596,7 @@ Lighthouse检测出所有资源仅约200KB，0.56秒。但该网站包含大约
 
 从我开始写core-js的一开始，我就一直在考虑创建一个Web服务，为浏览器提供所需的polyfill服务。
 
-未提供此类服务是core-js落后于另一个项目的唯一方面。英国《金融时报》的[polyfill-service](https://polyfill.io/)就基于这一概念，这是一个很牛的服务。这个项目的主要问题是，服务很牛，但是用了糟糕的polyfill。这个项目只是polyfill了core-js提供的ECMAScript功能的一小部分，大多数polyfill是第三方的，他们并不是为一起工作而设计的，太多polyfill没有正确遵循规范，或者太粗糙，或者使用起来很危险（例如，[WeakMap看样子是在一步步实现规范](https://github.com/Financial-Times/polyfill-library/blob/554248173eae7554ef0a7776549d2901f02a7d51/polyfill/WeakMap/polyfill.js)，但缺乏一些特别手段，使其导致内存泄漏和线性访问时间，这就不太好了，还有更多其他问题——它不是在IE11这类引擎中修补、修复和重用本地实现，而是不接受可迭代参数，[这使得WeakMap将会被完全替换](https://github.com/Financial-Times/polyfill-library/blob/554248173eae7554ef0a7776549d2901f02a7d51/polyfill/WeakMap/detect.js)）。一些优秀的开发人员时不时尝试修复这个问题，但是polyfill本身拥有的时间实在是太少了，因此它还远远达不到可被推荐的地步。
+未提供此类服务是core-js落后于另一个项目的唯一方面。[polyfill-service](https://cdnjs.cloudflare.com/polyfill/)就基于这一概念，这是一个很牛的服务。这个项目的主要问题是，服务很牛，但是用了糟糕的polyfill。这个项目只是polyfill了core-js提供的ECMAScript功能的一小部分，大多数polyfill是第三方的，他们并不是为一起工作而设计的，太多polyfill没有正确遵循规范，或者太粗糙，或者使用起来很危险（例如，[WeakMap看样子是在一步步实现规范](https://github.com/Financial-Times/polyfill-library/blob/554248173eae7554ef0a7776549d2901f02a7d51/polyfill/WeakMap/polyfill.js)，但缺乏一些特别手段，使其导致内存泄漏和线性访问时间，这就不太好了，还有更多其他问题——它不是在IE11这类引擎中修补、修复和重用本地实现，而是不接受可迭代参数，[这使得WeakMap将会被完全替换](https://github.com/Financial-Times/polyfill-library/blob/554248173eae7554ef0a7776549d2901f02a7d51/polyfill/WeakMap/detect.js)）。一些优秀的开发人员时不时尝试修复这个问题，但是polyfill本身拥有的时间实在是太少了，因此它还远远达不到可被推荐的地步。
 
 
 以适当的形式创建这样的服务需要制作和维护许多新组件。我独自一人从事core-js开发，项目没有得到任何公司的必要支持，开发纯粹是建立在热情之上，我需要资金来养活自己和家人，所以我没有时间和其他资源去开发它。然而，在其他任务范围内，我已经制作了一些必需的组件，与一些用户的讨论让我相信，创建一个最大限度简化的服务，然后在你自己的服务器上运行它就足够了。