Document a hack

src/Composer/Autoload/ClassLoader.php

@@ -197,6 +197,7 @@ class ClassLoader
      */
     public function findFile($class)
     {
+        // work around for PHP 5.3.0 - 5.3.2 https://bugs.php.net/50731
         if ('\\' == $class[0]) {
             $class = substr($class, 1);
         }