Add caveat emptor for peek method in Java directors

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@13838 626c5289-ae23-0410-ae9c-e8d60b6d4f22

Lib/java/director.swg

@@ -68,6 +68,7 @@ namespace Swig {
       weak_global_ = true;
     }
 
+    /* Only call peek if you know what you are doing wrt to weak/global references */
     jobject peek() {
       return jthis_;
     }