patch 9.1.0548: it's not possible to get a unique id for some vars

Problem:  it's not possible to get a unique id for some vars
Solution: Add the id() Vim script function, which returns a unique
          identifier for object, dict, list, job, blob or channel
          variables (Ernie Rael)

fixes: #14374
closes: #15145

Signed-off-by: Ernie Rael <errael@raelity.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/version9.txt b/runtime/doc/version9.txt
index 43de269..86ec020 100644
--- a/runtime/doc/version9.txt
+++ b/runtime/doc/version9.txt
@@ -1,4 +1,4 @@
-*version9.txt*  For Vim version 9.1.  Last change: 2024 Jul 08
+*version9.txt*  For Vim version 9.1.  Last change: 2024 Jul 09
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -41593,6 +41593,8 @@
 |foreach()|		apply function to List items
 |getregion()|		get a region of text from a buffer
 |getregionpos()|	get a list of positions for a region
+|id()|			get unique identifier for a Dict, List, Object,
+			Channel or Blob variable
 |matchbufline()|	all the matches of a pattern in a buffer
 |matchstrlist()|	all the matches of a pattern in a List of strings
 |popup_setbuf()|	switch to a different buffer in a popup