Point to bracket notation in description of list() language construct (#3957)

Author: driade

reference/array/functions/list.xml

@@ -25,6 +25,11 @@
     the numerical indices start at 0.
    </para>
   </note>
+  <para>
+   As of PHP 7.1.0, <function>list</function> can also contain explicit keys, allowing for the
+   destructuring of arrays with non-integer or non-sequential keys. For more details on
+   array destructuring, see the <link linkend="language.types.array">array destructuring section</link>.
+  </para>
  </refsect1>
  <refsect1 role="parameters">
   &reftitle.parameters;