[announce/2013.03.md] exerpt of changelog added

docs/announce/2013.03.md

@@ -17,11 +17,17 @@ code-named after Singapore.pm.
 
 Some of the changes in this release are outlined below:
 
-  + ...
-  + ...
-  + ...
+* Rakudo warns when pure expressions are used in sink context
+* .substr(...) now correctly accepts whatever-star closures
+* Implemented shellwords postcircumfix (%h<< $x 'foo bar' >>)
+* Defining operators spelled like the empty string is now illegal
+* Array interpolations now properly do LTM
+* Autothread "none" and "all" junctions before "any" and "one"
+* Helpful error if you write "else if" instead of "elsif"
+* Throw exception if a Range is used as a Range endpoint
+* Corrected argument order in IO.seek
 
-This is only a small of the changes in this release. For a more
+This is only some of the changes in this release. For a more
 detailed list, see "docs/ChangeLog".
 
 The development team thanks all of our contributors and sponsors for