[[ DefaultHandlers ]] Add release note

Author: livecodeali

notes/feature-default_handlers.md

@@ -0,0 +1,20 @@
+# Default handlers
+Objects no longer have default scripts that appear in the script
+editor when their empty scripts are edited. Instead, all the 
+associated message handlers for the object type now appear in a 
+list underneath the list of handlers that are present in the 
+script. When clicked, these lines add the selected default 
+handler to the end of the current script.
+
+If there is a default script for this handler and object type  
+in the appropriate location 
+(Toolset/resources/supporting_files/default_scripts/ for 
+'classic' objects, <widget_path>/support/ for widgets), the 
+content of the handler is obtained from that script (including
+preceding comments)
+
+If there is no default script for this handler and object type,
+the handler is constructed using information from the 
+documentation, namely the Summary element is used as a preceding 
+comment to describe the handler, and then the handler declared
+with all the specified parameters.