Fix internal link (#2668)

content/docs/concurrent-mode-adoption.md

@@ -80,7 +80,7 @@ ReactDOM.createRoot(
 >
 >Concurrent Mode APIs such as `createRoot` only exist in the experimental builds of React.
 
-In Concurrent Mode, the lifecycle methods [previously marked](https://reactjs.org/blog/2018/03/27/update-on-async-rendering.html) as "unsafe" actually *are* unsafe, and lead to bugs even more than in today's React. We don't recommend trying Concurrent Mode until your app is [Strict Mode](https://reactjs.org/docs/strict-mode.html)-compatible.
+In Concurrent Mode, the lifecycle methods [previously marked](/blog/2018/03/27/update-on-async-rendering.html) as "unsafe" actually *are* unsafe, and lead to bugs even more than in today's React. We don't recommend trying Concurrent Mode until your app is [Strict Mode](/docs/strict-mode.html)-compatible.
 
 ## What to Expect {#what-to-expect}
 

content/docs/how-to-contribute.md

@@ -21,7 +21,7 @@ All work on React happens directly on [GitHub](https://github.com/facebook/react
 
 ### Semantic Versioning {#semantic-versioning}
 
-React follows [semantic versioning](https://semver.org/). We release patch versions for critical bugfixes, minor versions for new features or non-essential changes, and major versions for any breaking changes. When we make breaking changes, we also introduce deprecation warnings in a minor version so that our users learn about the upcoming changes and migrate their code in advance. Learn more about our commitment to stability and incremental migration in [our versioning policy](https://reactjs.org/docs/faq-versioning.html).
+React follows [semantic versioning](https://semver.org/). We release patch versions for critical bugfixes, minor versions for new features or non-essential changes, and major versions for any breaking changes. When we make breaking changes, we also introduce deprecation warnings in a minor version so that our users learn about the upcoming changes and migrate their code in advance. Learn more about our commitment to stability and incremental migration in [our versioning policy](/docs/faq-versioning.html).
 
 Every significant change is documented in the [changelog file](https://github.com/facebook/react/blob/master/CHANGELOG.md).
 
@@ -56,7 +56,7 @@ Facebook has a [bounty program](https://www.facebook.com/whitehat/) for the safe
 ### How to Get in Touch {#how-to-get-in-touch}
 
 * IRC: [#reactjs on freenode](https://webchat.freenode.net/?channels=reactjs)
-* [Discussion forums](https://reactjs.org/community/support.html#popular-discussion-forums)
+* [Discussion forums](/community/support.html#popular-discussion-forums)
 
 There is also [an active community of React users on the Discord chat platform](https://www.reactiflux.com/) in case you need help with React.
 

content/docs/reference-profiler.md

@@ -7,11 +7,11 @@ permalink: docs/profiler.html
 ---
 
 The `Profiler` measures how often a React application renders and what the "cost" of rendering is.
-Its purpose is to help identify parts of an application that are slow and may benefit from [optimizations such as memoization](https://reactjs.org/docs/hooks-faq.html#how-to-memoize-calculations).
+Its purpose is to help identify parts of an application that are slow and may benefit from [optimizations such as memoization](/docs/hooks-faq.html#how-to-memoize-calculations).
 
 > Note:
 >
-> Profiling adds some additional overhead, so **it is disabled in [the production build](https://reactjs.org/docs/optimizing-performance.html#use-the-production-build)**.
+> Profiling adds some additional overhead, so **it is disabled in [the production build](/docs/optimizing-performance.html#use-the-production-build)**.
 >
 > To opt into production profiling, React provides a special production build with profiling enabled.
 > Read more about how to use this build at [fb.me/react-profiling](https://fb.me/react-profiling)

content/docs/refs-and-the-dom.md

@@ -161,7 +161,7 @@ class Parent extends React.Component {
 }
 ```
 
-If you want to allow people to take a `ref` to your function component, you can use [`forwardRef`](https://reactjs.org/docs/forwarding-refs.html) (possibly in conjunction with [`useImperativeHandle`](/docs/hooks-reference.html#useimperativehandle)), or you can convert the component to a class.
+If you want to allow people to take a `ref` to your function component, you can use [`forwardRef`](/docs/forwarding-refs.html) (possibly in conjunction with [`useImperativeHandle`](/docs/hooks-reference.html#useimperativehandle)), or you can convert the component to a class.
 
 You can, however, **use the `ref` attribute inside a function component** as long as you refer to a DOM element or a class component:
 

content/docs/testing-environments.md

@@ -29,7 +29,7 @@ A large portion of UI tests can be written with the above setup: using Jest as a
 
 If you're writing a library that tests mostly browser-specific behavior, and requires native browser behavior like layout or real inputs, you could use a framework like [mocha.](https://mochajs.org/)
 
-In an environment where you _can't_ simulate a DOM (e.g. testing React Native components on Node.js), you could use [event simulation helpers](https://reactjs.org/docs/test-utils.html#simulate) to simulate interactions with elements. Alternately, you could use the `fireEvent` helper from [`@testing-library/react-native`](https://testing-library.com/docs/native-testing-library).
+In an environment where you _can't_ simulate a DOM (e.g. testing React Native components on Node.js), you could use [event simulation helpers](/docs/test-utils.html#simulate) to simulate interactions with elements. Alternately, you could use the `fireEvent` helper from [`@testing-library/react-native`](https://testing-library.com/docs/native-testing-library).
 
 Frameworks like [Cypress](https://www.cypress.io/), [puppeteer](https://github.com/GoogleChrome/puppeteer) and [webdriver](https://www.seleniumhq.org/projects/webdriver/) are useful for running [end-to-end tests](#end-to-end-tests-aka-e2e-tests).