runtime(doc): add reference to extendnew() at extend()

related: #16607

Signed-off-by: Christian Brabandt <cb@256bit.org>

diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index e2d2f43b5ef3dc6c4016bbc03212102b82e72e5c..344dfdfd8866d6d6ab61e07aeebdf89bb81fe3f1 100644 (file)
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -1,4 +1,4 @@
-*builtin.txt*  For Vim version 9.1.  Last change: 2025 Feb 06
+*builtin.txt*  For Vim version 9.1.  Last change: 2025 Feb 17
 
 
                  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -3006,7 +3006,8 @@ extend({expr1}, {expr2} [, {expr3}])                      *extend()*
                When {expr3} is omitted then "force" is assumed.
 
                {expr1} is changed when {expr2} is not empty.  If necessary
-               make a copy of {expr1} first.
+               make a copy of {expr1} first or use |extendnew()| to return a
+               new List/Dictionary.
                {expr2} remains unchanged.
                When {expr1} is locked and {expr2} is not empty the operation
                fails.