runtime(doc): clarify the use of change marks when writing a buffer

related: #17008

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/motion.txt b/runtime/doc/motion.txt
index 4e57797..726d15d 100644
--- a/runtime/doc/motion.txt
+++ b/runtime/doc/motion.txt
@@ -1,4 +1,4 @@
-*motion.txt*    For Vim version 9.1.  Last change: 2024 Dec 17
+*motion.txt*    For Vim version 9.1.  Last change: 2025 Apr 03
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -895,12 +895,12 @@
 
 
 							*'[* *`[*
-'[  `[			To the first character of the previously changed
-			or yanked text.
+'[  `[			To the first character of the previously changed,
+			or yanked text.  Also set when writing the buffer.
 
 							*']* *`]*
 ']  `]			To the last character of the previously changed or
-			yanked text.
+			yanked text.  Also set when writing the buffer.
 
 After executing an operator the Cursor is put at the beginning of the text
 that was operated upon.  After a put command ("p" or "P") the cursor is