patch 9.0.1181: class inheritance and typing insufficiently tested

Problem:    Class inheritance and typing insufficiently tested.
Solution:   Add more tests.  Implement missing behavior.
diff --git a/src/version.c b/src/version.c
index 5036e07..898cc6b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1181,
+/**/
     1180,
 /**/
     1179,