docs(router): fix wording of hashchange explanation

Closes #7776

modules/angular2/src/router/router.ts

@@ -489,9 +489,11 @@ export class RootRouter extends Router {
                       emitPath = '/' + emitPath;
                     }
 
-                    // Because we've opted to use All hashchange events occur outside Angular.
+                    // We've opted to use pushstate and popState APIs regardless of whether you
+                    // an app uses HashLocationStrategy or PathLocationStrategy.
                     // However, apps that are migrating might have hash links that operate outside
                     // angular to which routing must respond.
+                    // Therefore we know that all hashchange events occur outside Angular.
                     // To support these cases where we respond to hashchanges and redirect as a
                     // result, we need to replace the top item on the stack.
                     if (change['type'] == 'hashchange') {