minor fix to release notes [ci skip]

Author: KrisThielemans

documentation/release_6.4.htm

@@ -59,7 +59,7 @@ <h4>Changes to examples</h4>
   <h3>Bug fixes</h3>
   <ul>
       <li>
-    Fixed a memory leak caused multiple calls to ProjDataInfo::clone() combined with dynamic_cast. 
+    Fixed a (small) memory leak in <code>ScatterSimulation::set_up()</code> caused by multiple calls to <code>ProjDataInfo::clone()</code> combined with <code>dynamic_cast</code>. 
     The object is now cloned once and owndership is transferred safely after type checking.
        </li>
     <br>