mention that handlebars syntax is intentionally limited, fixes vuejs#459

Author: chrisvfritz

src/guide/comparison.md

@@ -294,7 +294,7 @@ That said, it would probably make a better comparison between Vue core and Ember
 
 - Vue provides unobtrusive reactivity on plain JavaScript objects and fully automatic computed properties. In Ember, you need to wrap everything in Ember Objects and manually declare dependencies for computed properties.
 
-- Vue's template syntax harnesses the full power of JavaScript expressions, while Handlebars' expression and helper syntax is quite limited in comparison.
+- Vue's template syntax harnesses the full power of JavaScript expressions, while Handlebars' expression and helper syntax is intentionally quite limited in comparison.
 
 - Performance-wise, Vue outperforms Ember by a fair margin, even after the latest Glimmer engine update in Ember 2.0. Vue automatically batches updates, while in Ember you need to manually manage run loops in performance-critical situations.