docs(rootScope): grammar, clarity

src/ng/rootScope.js

@@ -55,8 +55,9 @@
  * @description
  *
  * Every application has a single root {@link ng.$rootScope.Scope scope}.
- * All other scopes are child scopes of the root scope. Scopes provide mechanism for watching the model and provide
- * event processing life cycle. See {@link guide/scope developer guide on scopes}.
+ * All other scopes are child scopes of the root scope. Scopes provide a mechanism for
+ * watching the model for changes and provide an event processing life cycle. See the
+ * {@link guide/scope developer guide on scopes}.
  */
 function $RootScopeProvider(){
   var TTL = 10;