docs: remove testing playground extension links

docs/queries/about.mdx

@@ -318,8 +318,9 @@ can contain options that affect the precision of string matching:
 - `exact`: Defaults to `true`; matches full strings, case-sensitive. When false,
   matches substrings and is not case-sensitive.
   - it has no effect when used together with `regex` or `function` arguments.
-  - in most cases, using a regex instead of a string combined with `{ exact: false }`
-    gives you more control over fuzzy matching so it should be preferred.
+  - in most cases, using a regex instead of a string combined with
+    `{ exact: false }` gives you more control over fuzzy matching so it should
+    be preferred.
 - `normalizer`: An optional function which overrides normalization behavior. See
   [`Normalization`](#normalization).
 
@@ -383,17 +384,6 @@ const {container} = render(<MyComponent />)
 const foo = container.querySelector('[data-foo="bar"]')
 ```
 
-## Browser extension
-
-Do you still have problems knowing how to use Testing Library queries?
-
-There is a very cool Browser extension for Chrome named
-[Testing Playground](https://chrome.google.com/webstore/detail/testing-playground/hejbmebodbijjdhflfknehhcgaklhano),
-and it helps you find the best queries to select elements. It allows you to
-inspect the element hierarchies in the Browser's Developer Tools, and provides
-you with suggestions on how to select them, while encouraging good testing
-practices.
-
 ## Playground
 
 If you want to get more familiar with these queries, you can try them out on

docs/react-testing-library/migrate-from-enzyme.mdx

@@ -262,14 +262,9 @@ which explains [which query to use](queries/about.mdx#priority), so check it
 out!
 
 If you still have a question about which of React Testing Library's queries to
-use, then check out [testing-playground.com](https://testing-playground.com) and
-the accompanying Chrome extension
-**[Testing Playground](https://chrome.google.com/webstore/detail/testing-playground/hejbmebodbijjdhflfknehhcgaklhano)**
-which aims to enable developers to find the best query when writing tests. It
-also helps you find the best queries to select elements. It allows you to
-inspect the element hierarchies in the Chrome Developer Tools and provides you
-with suggestions on how to select them, all while encouraging good testing
-practices.
+use, then check out [testing-playground.com](https://testing-playground.com).
+Testing Playground helps you find the best queries to select elements, while
+encouraging good testing practices.
 
 ## Using act() and wrapper.update()