添加PR链接

note/0前言.md

@@ -9,6 +9,7 @@
 * [https://github.com/vuejs/vue/pull/6795](https://github.com/vuejs/vue/pull/6795)
 * [https://github.com/vuejs/vue/pull/6833](https://github.com/vuejs/vue/pull/6833)
 * [https://github.com/vuejs/vue/pull/7308](https://github.com/vuejs/vue/pull/7308)
+* [https://github.com/vuejs/vue/pull/7762](https://github.com/vuejs/vue/pull/7762)
 
 #### 为什么要阅读源码？