Update CHANGELOG

Author: José Valim

CHANGELOG.md

@@ -1,6 +1,7 @@
 # v0.9.3.dev
 
 * enhancements
+  * [File] Add `File.chgrp`, `File.chmod` and `File.chown`
   * [Kernel] Add --warnings-as-errors to Elixir's compiler options
   * [Kernel] Print warnings to stderr
   * [Kernel] Warn on undefined module attributes
@@ -16,7 +17,8 @@
   * [Kernel] Improve error messages on default clauses clash
   * [Kernel] `__MODULE__.Foo` now returns `Foo` when outside of a Module
   * [Kernel] Improve error messages when default clauses from different definitions collide
-  * [Kernel] ^x variables should always refer to the value before the expression
+  * [Kernel] `^x` variables should always refer to the value before the expression
+  * [Kernel] Allow `(x, y) when z` in function clauses and try expressions
   * [Mix] Mix now properly evaluates rebar scripts
 
 * deprecations