[docs] Remove generic spread, Object.assign mentions

docs/02.2-jsx-spread.md

@@ -49,23 +49,4 @@ You can use this multiple times or combine it with other attributes. The specifi
 
 ## What's with the weird `...` notation?
 
-The `...` operator (or spread operator) is already supported for [arrays in ES6](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator). There is also an ES7 proposal for [Object Rest and Spread Properties](https://github.com/sebmarkbage/ecmascript-rest-spread).
-
-In fact, you can already use this in our code base as an experimental syntax:
-
-```javascript
-  var oldObj = { foo: 'hello', bar: 'world' };
-  var newObj = { ...oldObj, foo: 'hi' };
-  console.log(newObj.foo); // 'hi';
-  console.log(newObj.bar); // 'world';
-```
-
-Merging two objects can be expressed as:
-
-```javascript
-  var ab = { ...a, ...b };
-```
-
-> Note:
->
-> Use the [JSX command-line tool](http://npmjs.org/package/react-tools) with the `--harmony` flag to activate the experimental ES7 syntax.
+The `...` operator (or spread operator) is already supported for [arrays in ES6](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator). There is also an ES7 proposal for [Object Rest and Spread Properties](https://github.com/sebmarkbage/ecmascript-rest-spread). We're taking advantage of these supported and developing standards in order to provide a cleaner syntax in JSX.