Remove interface list, the ToC shows the same info

Author: Girgias

reference/spl/interfaces.xml

@@ -9,18 +9,6 @@
    and a pair of interfaces to implement the Observer Design Pattern.
   </simpara>
 
-  <section xml:id="spl.interfaces.list">
-   <title>Interface list</title>
-
-   <simplelist>
-    <member><interfacename>OuterIterator</interfacename></member>
-    <member><interfacename>RecursiveIterator</interfacename></member>
-    <member><interfacename>SeekableIterator</interfacename></member>
-    <member><interfacename>SplObserver</interfacename></member>
-    <member><interfacename>SplSubject</interfacename></member>
-   </simplelist>
-  </section>
-
   <section role="seealso">
    &reftitle.seealso;
    <simplelist>