chore(docs): specify how ngClass deals with natural CSS transitions

Author: matsko

src/ng/directive/ngClass.js

@@ -193,10 +193,10 @@ function classDirective(name, selector) {
 
    ## ngClass and pre-existing CSS3 Transitions/Animations
    The ngClass directive still supports CSS3 Transitions/Animations even if they do not follow the ngAnimate CSS naming structure.
-   Therefore, if any CSS3 Transition/Animation styles (outside of ngAnimate) are set on the element, then, if a ngClass animation
-   is triggered, the ngClass animation will be skipped so that ngAnimate can allow for the pre-existing transition or animation to
-   take over. This restriction allows for ngClass to still work with standard CSS3 Transitions/Animations that are defined
-   outside of ngAnimate.
+   Upon animation ngAnimate will apply supplementary CSS classes to track the start and end of an animation, but this will not hinder
+   any pre-existing CSS transitions already on the element. To get an idea of what happens during a class-based animation, be sure
+   to view the step by step details of {@link ngAnimate.$animate#methods_addclass $animate.addClass} and
+   {@link ngAnimate.$animate#methods_removeclass $animate.removeClass}.
  */
 var ngClassDirective = classDirective('', true);