Improve the doc on how to do type-checking for test files (#10705)

Author: akphi

README.md

@@ -198,7 +198,7 @@ module.exports = {
 };
 ```
 
-However, there are some [caveats](https://babeljs.io/docs/en/babel-plugin-transform-typescript#caveats) to using TypeScript with Babel. Because TypeScript support in Babel is transpilation, Jest will not type-check your tests as they are run. If you want that, you can use [ts-jest](https://github.com/kulshekhar/ts-jest).
+However, there are some [caveats](https://babeljs.io/docs/en/babel-plugin-transform-typescript#caveats) to using TypeScript with Babel. Because TypeScript support in Babel is purely transpilation, Jest will not type-check your tests as they are run. If you want that, you can use [ts-jest](https://github.com/kulshekhar/ts-jest) instead, or just run the TypeScript compiler [tsc](https://www.typescriptlang.org/docs/handbook/compiler-options.html) separately (or as part of your build process).
 
 <!-- end copied -->
 

docs/GettingStarted.md

@@ -170,4 +170,4 @@ module.exports = {
 };
 ```
 
-However, there are some [caveats](https://babeljs.io/docs/en/babel-plugin-transform-typescript#caveats) to using TypeScript with Babel. Because TypeScript support in Babel is transpilation, Jest will not type-check your tests as they are run. If you want that, you can use [ts-jest](https://github.com/kulshekhar/ts-jest).
+However, there are some [caveats](https://babeljs.io/docs/en/babel-plugin-transform-typescript#caveats) to using TypeScript with Babel. Because TypeScript support in Babel is purely transpilation, Jest will not type-check your tests as they are run. If you want that, you can use [ts-jest](https://github.com/kulshekhar/ts-jest) instead, or just run the TypeScript compiler [tsc](https://www.typescriptlang.org/docs/handbook/compiler-options.html) separately (or as part of your build process).

website/versioned_docs/version-24.x/GettingStarted.md

@@ -171,4 +171,4 @@ module.exports = {
 };
 ```
 
-However, there are some [caveats](https://babeljs.io/docs/en/babel-plugin-transform-typescript#caveats) to using TypeScript with Babel. Because TypeScript support in Babel is transpilation, Jest will not type-check your tests as they are run. If you want that, you can use [ts-jest](https://github.com/kulshekhar/ts-jest).
+However, there are some [caveats](https://babeljs.io/docs/en/babel-plugin-transform-typescript#caveats) to using TypeScript with Babel. Because TypeScript support in Babel is purely transpilation, Jest will not type-check your tests as they are run. If you want that, you can use [ts-jest](https://github.com/kulshekhar/ts-jest) instead, or just run the TypeScript compiler [tsc](https://www.typescriptlang.org/docs/handbook/compiler-options.html) separately (or as part of your build process).