SF bug #951482:  New module: doc versus action

Strengthen the warnings about creating bogus objects using the new module.
diff --git a/Doc/lib/libnew.tex b/Doc/lib/libnew.tex
index 67bfb2e..f1ff7ea 100644
--- a/Doc/lib/libnew.tex
+++ b/Doc/lib/libnew.tex
@@ -11,6 +11,8 @@
 when a new object needs to be created ``magically'' and not by using the
 regular creation functions. This module provides a low-level interface
 to the interpreter, so care must be exercised when using this module.
+It is possible to supply non-sensical arguments which crash the
+interpreter when the object is used.
 
 The \module{new} module defines the following functions: