Fix return type of streamWrapper::stream_cast

Author: nielsdos

reference/stream/streamwrapper/stream-cast.xml

@@ -10,7 +10,7 @@
  <refsect1 role="description">
   &reftitle.description;
   <methodsynopsis>
-   <modifier>public</modifier> <type>resource</type><methodname>streamWrapper::stream_cast</methodname>
+   <modifier>public</modifier> <type class="union"><type>resource</type><type>false</type></type><methodname>streamWrapper::stream_cast</methodname>
    <methodparam><type>int</type><parameter>cast_as</parameter></methodparam>
   </methodsynopsis>
   <para>