Ensure 'module removed' warning messages contain the word 'module' or 'package'.

This should fix the test_py3kwarn failure on OS X.  test_support.import_module
also requires this.
diff --git a/Mac/Modules/Nav.c b/Mac/Modules/Nav.c
index 1c17776..f7b19b9 100644
--- a/Mac/Modules/Nav.c
+++ b/Mac/Modules/Nav.c
@@ -932,7 +932,7 @@
 {
 	PyObject *m, *d;
 	
-	if (PyErr_WarnPy3k("In 3.x, Nav is removed.", 1))
+	if (PyErr_WarnPy3k("In 3.x, the Nav module is removed.", 1))
 		return;
 
 #ifdef __LP64__