Add NEWS entry about incompatible sorting command behaviors

diff --git a/etc/NEWS b/etc/NEWS
index b0758b60a098bf7812fbec607358b7b760ee7ab2..73e61aab32706848c923c635d155e516dfb91359 100644 (file)
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -135,6 +135,14 @@ of 'user-emacs-directory'.
 \f
 * Incompatible changes in Emacs 29.1
 
+---
+** Sorting commands no longer necessarily change modification status.
+In earlier Emacs versions, commands like 'M-x sort-lines' would always
+change buffer modification status to "modified", whether they changed
+something in the buffer or not.  This has been changed: The buffer is
+marked as modified only if the sorting ended up changing the contents
+of the buffer.
+
 ---
 ** 'string-lines' handles trailing newlines differently.
 It no longer returns an empty final string if the string ends with a