patch 9.0.1126: bracketed paste can be enabled when it is not recognized

Problem:    Bracketed paste can be enabled when pasted text is not recognized.
Solution:   Output t_BE only when t_PS and t_PE are set.
diff --git a/runtime/doc/term.txt b/runtime/doc/term.txt
index f519bed..8b8214c 100644
--- a/runtime/doc/term.txt
+++ b/runtime/doc/term.txt
@@ -1,4 +1,4 @@
-*term.txt*      For Vim version 9.0.  Last change: 2022 Dec 31
+*term.txt*      For Vim version 9.0.  Last change: 2023 Jan 01
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -118,6 +118,10 @@
 If this is done while Vim is running the 't_BD' will be sent to the terminal
 to disable bracketed paste.
 
+If |t_PS| or |t_PE| is not set, then |t_BE| will not be used.  This is to make
+sure that bracketed paste is not enabled when the escape codes surrounding
+pasted text cannot be recognized.
+
 If your terminal supports bracketed paste, but the options are not set
 automatically, you can try using something like this: >