Info about new hook to change log

ChangeLog

@@ -480,6 +480,7 @@ Version 1.5.1 -- CVS
   - Allow double quote to be used in MOTD (#1276959).
   - Prevent right_frame to be set to '//www.example.com'.
   - Tweak printer friendly attachment view.
+  - Added new compose_send_after hook.
 
 Version 1.5.0 - 2 February 2004
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