patch 9.1.0148: Vim9: can't call internal methods with objects

Problem:  Vim9: can't call internal methods with objects
Solution: Add support for empty(), len() and string() function
          calls for objects (Yegappan Lakshmanan)

closes: #14129

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/version9.txt b/runtime/doc/version9.txt
index 7947cb2..bf16d49 100644
--- a/runtime/doc/version9.txt
+++ b/runtime/doc/version9.txt
@@ -41543,6 +41543,11 @@
 
 Support for Wayland UI.
 
+Vim9 script
+-----------
+Add support for internal builtin functions with vim9 objects, see
+|builtin-object-methods|
+
 Other improvements				*new-other-9.2*
 ------------------