docs: recommend installing @types/react (#1390)

Author: MatanBobi

docs/react-testing-library/intro.mdx

@@ -15,10 +15,10 @@ npm install --save-dev @testing-library/react
 
 ### With TypeScript
 
-To get full type coverage, you need to install the types for `react-dom` as well:
+To get full type coverage, you need to install the types for `react` and `react-dom` as well:
 
 ```bash npm2yarn
-npm install --save-dev @testing-library/react @types/react-dom
+npm install --save-dev @testing-library/react @types/react-dom @types/react
 ```