minor #10521 Adding a sample tsconfig file to the Encore documentation page (iammichiel)

This PR was submitted for the master branch but it was merged into the 3.4 branch instead (closes #10521).

Discussion
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Adding a sample tsconfig file to the Encore documentation page

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Commits
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a4dd5e4 Adding a sample tsconfig file to the Encore documentation page

Author: javiereguiluz

frontend/encore/typescript.rst

@@ -26,11 +26,14 @@ Encore, you're done!
 
 Any ``.ts`` files that you require will be processed correctly. You can
 also configure the `ts-loader options`_ via the ``enableTypeScriptLoader()``
-method. See the `Encore's index.js file`_ for detailed documentation.
+method. See the `Encore's index.js file`_ for detailed documentation and check
+out the `tsconfig.json reference`_ and the `Webpack guide about Typescript`_.
 
 If React is enabled (``.enableReactPreset()``), any ``.tsx`` file will also be
 processed by ``ts-loader``.
 
 .. _`TypeScript`: https://www.typescriptlang.org/
 .. _`ts-loader options`: https://github.com/TypeStrong/ts-loader#options
 .. _`Encore's index.js file`: https://github.com/symfony/webpack-encore/blob/master/index.js
+.. _`tsconfig.json reference`: https://www.typescriptlang.org/docs/handbook/tsconfig-json.html
+.. _`Webpack guide about Typescript`: https://webpack.js.org/guides/typescript/