chore(doc-gen): read `.es6` files as well as `.js` when generating docs

Closes #1429

docs/dgeni-package/index.js

@@ -60,6 +60,8 @@ module.exports = new Package('angular', [jsdocPackage, nunjucksPackage])
   readFilesProcessor.sourceFiles = [
     { include: 'modules/*/*.js', basePath: 'modules' },
     { include: 'modules/*/src/**/*.js', basePath: 'modules' },
+    { include: 'modules/*/*.es6', basePath: 'modules' },
+    { include: 'modules/*/src/**/*.es6', basePath: 'modules' },
     { include: 'modules/*/docs/**/*.md', basePath: 'modules' },
     { include: 'docs/content/**/*.md', basePath: 'docs/content' }
   ];

docs/dgeni-package/readers/atScript.js

@@ -10,7 +10,7 @@ var path = require('canonical-path');
 module.exports = function atScriptFileReader(log, atParser, modules) {
   var reader = {
     name: 'atScriptFileReader',
-    defaultPattern: /\.js$/,
+    defaultPattern: /\.js|\.es6$/,
     getDocs: function(fileInfo) {
 
       var moduleDoc = atParser.parseModule(fileInfo);