patch 9.1.0120: hard to get visual region using Vim script

Problem:  hard to get visual region using Vim script
Solution: Add getregion() Vim script function
          (Shougo Matsushita, Jakub Łuczyński)

closes: #13998
closes: #11579

Co-authored-by: =?UTF-8?q?Jakub=20=C5=81uczy=C5=84ski?= <doubleloop@o2.pl>
Co-authored-by: Shougo Matsushita <Shougo.Matsu@gmail.com>
Signed-off-by: Shougo Matsushita <Shougo.Matsu@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/usr_41.txt b/runtime/doc/usr_41.txt
index 0ca19be..0d832a3 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 Feb 01
+*usr_41.txt*	For Vim version 9.1.  Last change: 2024 Feb 20
 
 		     VIM USER MANUAL - by Bram Moolenaar
 
@@ -929,6 +929,7 @@
 
 Working with text in the current buffer:		*text-functions*
 	getline()		get a line or list of lines from the buffer
+	getregion()		get a region of text from the buffer
 	setline()		replace a line in the buffer
 	append()		append line or list of lines in the buffer
 	indent()		indent of a specific line