Mentioning null-aware in 1.12 changelog

CHANGELOG.md

Index: CHANGELOG.md
diff --git a/CHANGELOG.md b/CHANGELOG.md
index aea1b007223c862979796977704a0f0a752d0cde..d7ef690c59fac7e915a6e8ca4fa5aef60be39dd9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,14 @@
 
 ## 1.12.0
 
+### Language changes
+
+* Null-aware operators
+    * `??`: if null operator. `expr1 ?? expr2` evaluates to `expr1` if not `null`, otherwise `expr2`.
+    * `??=`: null-aware assignment. `v ??= expr` causes `v` to be assigned `expr` only if `v` is `null`.
+    * `x?.p`: null-aware access. `x?.p` evaluates to `x.p` if `x` is not `null`, otherwise evaluates to `null`.
+    * `x?.m()`: null-aware method invocation. `x?.m()` invokes `m` only if `x` is not `null`.

[eernst, 2015/08/25 12:28:36]

You could say that the reader of this announcement could as well go to the spec
and read about the details, so maybe there is no need to have this summary here.

Otherwise, it might be nice to make it explicitly inofficial: "

```
* Null-aware operators implemented. Informal summary of the semantics:
    * `??`: ...
```

+
 ### Core library changes
 
 * `dart:async`