Minor reword

Author: javiereguiluz

frontend/encore/babel.rst

@@ -16,9 +16,8 @@ Need to extend the Babel configuration further? The easiest way is via
     Encore
         // ...
         
-        // make sure to install any presets you want to use
-        // yarn add babel-preset-es2017
-        // modify the default Babel configuration
+        // first, install any presets you want to use (e.g. yarn add babel-preset-es2017)
+        // then, modify the default Babel configuration
         .configureBabel(function(babelConfig) {
             babelConfig.presets.push('es2017');
         })