Added details of dartfmt change to 1.15 changelog

CHANGELOG.md

 ## 1.16.0
 
 ### Analyzer
 
 *   Static checking of `for in` statements. These will now produce static
     warnings:
 
     ```dart
     // Not Iterable.
     for (var i in 1234) { ... }
@@ skipping 20 matching lines @@
     `SecurityContext.setClientAuthoritiesBytes`.
   * **Breaking** The named `directory` argument of
     `SecurityContext.setTrustedCertificates` has been removed.
   * Added support to `SecurityContext` for PKCS12 certificate and key
     containers.
   * All calls in `SecurityContext` that accept certificate data now accept an
     optional named parameter `password`, similar to
     `SecurityContext.usePrivateKeyBytes`, for use as the password for PKCS12
     data.
 
-### Dartium
+### Tool changes
 
+* Dartium and content shell
   * The Chrome-based tools that ship as part of the Dart SDK – Dartium and
     content shell – are now based on Chrome version 45 (instead of Chrome 39).
-  * Dart browser libraries (`dart:html`, `dart:svg`, etc) have not been updated.
+  * Dart browser libraries (`dart:html`, `dart:svg`, etc) *have not* been
+    updated.
     * These are still based on Chrome 39.
     * These APIs will be updated in a future release.
   * Note that there are experimental APIs which have changed in the underlying
     browser, and will not work with the older libraries.
     For example, `Element.animate`.
 
+* `dartfmt` - upgraded to v0.2.4
+  * Better handling for long collections with comments.
+  * Always put member metadata annotations on their own line.
+  * Indent functions in named argument lists with non-functions.
+  * Force the parameter list to split if a split occurs inside a function-typed
+    parameter.
+  * Don't force a split for before a single named argument if the argument
+    itself splits.
+
 ### Service protocol changes
 
 * Fixed a documentation bug where the field `extensionRPCs` in `Isolate`
   was not marked optional.
 
 ### Experimental language features
   * Added support for [configuration-specific imports](https://github.com/munificent/dep-interface-libraries/blob/master/Proposal.md).
     On the VM and `dart2js`, they can be enabled with `--conditional-directives`.
 
     The analyzer requires additional configuration:
@@ skipping 784 matching lines @@
     they will keep the Dart process alive until they time out. This fixes the
     handling of persistent connections. Previously, the client would shut down
     immediately after a request.
 
   * **Breaking change:** `HttpServer` no longer compresses all traffic by
     default. The new `autoCompress` property can be set to `true` to re-enable
     compression.
 
 * `dart:isolate`: `Isolate.spawnUri` added the optional `packageRoot` argument,
   which controls how it resolves `package:` URIs.