fix dead link

Author: yyx990803

src/guide/extras/animation.md

@@ -7,7 +7,7 @@ import AnimateWatcher from './demos/AnimateWatcher.vue'
 
 # Animation Techniques
 
-Vue provides the [`<Transition>`](/guide/built-ins/transition.html) and [`<TransitionGroup>`](guide/built-ins/transition-group.html) components for handling enter / leave and list transitions. However, there are many other ways of using animations on the web, even in a Vue application. Here we will discuss a few additional techniques.
+Vue provides the [`<Transition>`](/guide/built-ins/transition.html) and [`<TransitionGroup>`](/guide/built-ins/transition-group.html) components for handling enter / leave and list transitions. However, there are many other ways of using animations on the web, even in a Vue application. Here we will discuss a few additional techniques.
 
 ## Class-based Animations