Tweak syntax doc (#1539)

* Tweak syntax doc

* Shorter version

Author: gaearon

packages/react-scripts/template/README.md

@@ -175,12 +175,14 @@ You don’t have to ever use `eject`. The curated feature set is suitable for sm
 
 ## Supported Language Features and Polyfills
 
-This project supports a superset of the latest JavaScript standard, which includes async and await.  
-In addition to ES2017, it also supports:
+This project supports a superset of the latest JavaScript standard.  
+In addition to [ES6](https://github.com/lukehoban/es6features) syntax features, it also supports:
 
-* [JSX](https://facebook.github.io/react/docs/introducing-jsx.html) and [Flow](https://flowtype.org/) syntax.
-* [Class Fields and Static Properties](https://github.com/tc39/proposal-class-public-fields) (stage 2 proposal).
+* [Exponentiation Operator](https://github.com/rwaldron/exponentiation-operator) (ES2016).
+* [Async/await](https://github.com/tc39/ecmascript-asyncawait) (ES2017).
 * [Object Rest/Spread Properties](https://github.com/sebmarkbage/ecmascript-rest-spread) (stage 3 proposal).
+* [Class Fields and Static Properties](https://github.com/tc39/proposal-class-public-fields) (stage 2 proposal).
+* [JSX](https://facebook.github.io/react/docs/introducing-jsx.html) and [Flow](https://flowtype.org/) syntax.
 
 Learn more about [different proposal stages](https://babeljs.io/docs/plugins/#presets-stage-x-experimental-presets-).