patch 9.1.0071: Need a diff() Vim script function

Problem:  Need a diff() Vim script function
Solution: Add the diff() Vim script function using the
          xdiff internal diff library, add support for
          "unified" and "indices" mode.
          (Yegappan Lakshmanan)

fixes: #4241
closes: #12321

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/usr_41.txt b/runtime/doc/usr_41.txt
index 0990a06..0ca19be 100644
--- a/runtime/doc/usr_41.txt
+++ b/runtime/doc/usr_41.txt
@@ -1,4 +1,4 @@
-*usr_41.txt*	For Vim version 9.1.  Last change: 2024 Jan 13
+*usr_41.txt*	For Vim version 9.1.  Last change: 2024 Feb 01
 
 		     VIM USER MANUAL - by Bram Moolenaar
 
@@ -1368,6 +1368,7 @@
 	changenr()		return number of most recent change
 	cscope_connection()	check if a cscope connection exists
 	did_filetype()		check if a FileType autocommand was used
+	diff()			diff two Lists of strings
 	eventhandler()		check if invoked by an event handler
 	getpid()		get process ID of Vim
 	getscriptinfo()		get list of sourced vim scripts