Merge branch '3.4' into 4.4

* 3.4:
  Update reactjs.rst
  Add link to SymfonyCasts React.js tutorial
  Update vuejs.rst

Author: javiereguiluz

frontend/encore/reactjs.rst

@@ -1,7 +1,19 @@
 Enabling React.js
 =================
 
-Using React? First enable support for it in ``webpack.config.js``:
+.. admonition:: Screencast
+    :class: screencast
+
+    Do you prefer video tutorials? Check out the `React.js screencast series`_.
+
+Using React? First add some dependencies with Yarn:
+
+.. code-block:: terminal
+
+    $ yarn add @babel/preset-react --dev
+    $ yarn add react react-dom prop-types
+
+Enable react in your ``webpack.config.js``:
 
 .. code-block:: terminal
 
@@ -26,3 +38,5 @@ install any missing dependencies. After running that command and restarting
 Encore, you're done!
 
 Your ``.js`` and ``.jsx`` files will now be transformed through ``babel-preset-react``.
+
+.. _`React.js screencast series`: https://symfonycasts.com/screencast/reactjs

frontend/encore/vuejs.rst

@@ -1,6 +1,11 @@
 Enabling Vue.js (``vue-loader``)
 ================================
 
+.. admonition:: Screencast
+    :class: screencast
+
+    Do you prefer video tutorials? Check out the `Vue screencast series`_.
+
 Want to use `Vue.js`_? No problem! First enable it in ``webpack.config.js``:
 
 .. code-block:: diff
@@ -156,3 +161,4 @@ you can import them with ``require()`` function:
 .. _`JSX with Vue.js`: https://github.com/vuejs/jsx
 .. _`Scoped Styles`: https://vue-loader.vuejs.org/guide/scoped-css.html
 .. _`CSS Modules`: https://github.com/css-modules/css-modules
+.. _`Vue screencast series`: https://symfonycasts.com/screencast/vue