Update Symfony browserlists reccomendation to browserlists standard.

Author: Taminoful

frontend/encore/postcss.rst

@@ -63,6 +63,16 @@ The ``autoprefixer`` (and many other tools) need to know what browsers you want
 support. The best-practice is to configure this directly in your ``package.json``
 (so that all the tools can read this):
 
+.. code-block:: diff
+
+    {
+    +  "browserslist": [
+    +    "defaults"
+    +  ]
+    }
+
+The ``defaults`` option is reccommended for most users and would be equivilant to the following browserslist.
+
 .. code-block:: diff
 
     {