"instances" vs "instance" (#301)

Author: marktinsley

src/guide/application.md

@@ -72,7 +72,7 @@ All Vue instances can have their raw `$data` directly serialized with `JSON.stri
 
 ## State Management
 
-In large applications, state management often becomes complex due to multiple pieces of state scattered across many components and the interactions between them. It is often overlooked that the source of truth in Vue.js applications is the raw data object - a Vue instances simply proxies access to it. Therefore, if you have a piece of state that should be shared by multiple instances, you should avoid duplicating it. Instead, share it by identity:
+In large applications, state management often becomes complex due to multiple pieces of state scattered across many components and the interactions between them. It is often overlooked that the source of truth in Vue.js applications is the raw data object - a Vue instance simply proxies access to it. Therefore, if you have a piece of state that should be shared by multiple instances, you should avoid duplicating it. Instead, share it by identity:
 
 ``` js
 var sourceOfTruth = {}