patch 9.1.0207: No autocommand when writing session file

Problem:  No autocommand when writing session file
Solution: Add SessionWritePost autocommand
          (Colin Kennedy)

fixes: ##14242
closes: #14288

Co-authored-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Colin Kennedy <colinvfx@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/version9.txt b/runtime/doc/version9.txt
index bf16d49..b94d157 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 Mar 03
+*version9.txt*  For Vim version 9.1.  Last change: 2024 Mar 26
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -41570,6 +41570,7 @@
 
 Autocommands: ~
 
+|SessionWritePost|	after writing the session file |:mksession|
 |TermResponseAll|	after the terminal response to |t_RV| and others is
 			received
 |WinNewPre|		before creating a new window