ES6 style: fix some nits from phistuck@ on chromium-dev@

docs/es6_chromium.md

 <!-- Feature template markdown:
 ## Header
 
 **Usage Example:**
 
 ```js
 
 ```
 
 **Documentation:** [link]()
@@ skipping 114 matching lines @@
   if (isLoaded()) {
     resolve();
   } else {
     document.onreadystatechange = function() {
       if (isLoaded()) resolve();
     };
   }
 });
 
 // ... some time later ...
-loaded.then(startTheApp).then(maybeShowFirstRun);
+fullyLoaded.then(startTheApp).then(maybeShowFirstRun);
 ```
 
 **Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-promise-objects)
 [link](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise)
 
 **Discussion Notes:** Feature already extensively used prior to creation of
 this document.
 
 ---
 
@@ skipping 483 matching lines @@
 **Discussion Notes / Link to Thread:**
 
 ---
 
 ## Object Static Methods
 
 **Usage Example:**
 
 ```js
 // Object.assign
-var o = Object.assign({a:true}, {b:true}, {c:true});
+var o = Object.assign({a:true}, {b:true}, {c:true});  // {a: true, b: true, c: true}
 'a' in o && 'b' in o && 'c' in o;  // true
 
 // Object.setPrototypeOf
 Object.setPrototypeOf({}, Array.prototype) instanceof Array;  // true
 
 // Object.is
+Object.is(null, null)  // true
+Object.is(NaN, NaN)  // true
+Object.is(-0, +0)  // false, btw: -0 === +0 is true
+
 // Object.getOwnPropertySymbols
 ```
 
 **Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-properties-of-the-object-constructor)
 
 **Discussion Notes / Link to Thread:**
 
 ---
 
 ## String Static & Prototype methods
@@ skipping 289 matching lines @@
 
 ```js
 // See Doc
 ```
 
 **Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-math)
 
 **Discussion Notes / Link to Thread:**
 
 ---