patch 9.0.1031: Vim9 class is not implemented yet

Problem:    Vim9 class is not implemented yet.
Solution:   Add very basic class support.
diff --git a/src/if_py_both.h b/src/if_py_both.h
index 5589af6..8dd7f09 100644
--- a/src/if_py_both.h
+++ b/src/if_py_both.h
@@ -6422,6 +6422,8 @@
 	case VAR_CHANNEL:
 	case VAR_JOB:
 	case VAR_INSTR:
+	case VAR_CLASS:
+	case VAR_OBJECT:
 	    Py_INCREF(Py_None);
 	    return Py_None;
 	case VAR_BOOL: