Merge pull request #301 from vuejs/master

Correct spelling error (#659)

Author: dingyiming

src/v2/api/index.md

@@ -766,7 +766,7 @@ All lifecycle hooks automatically have their `this` context bound to the instanc
 
   Specify the parent instance for the instance to be created. Establishes a parent-child relationship between the two. The parent will be accessible as `this.$parent` for the child, and the child will be pushed into the parent's `$children` array.
 
-  <p class="tip">Use `$parent` and `$children` sparringly - they mostly serve as an escape-hatch. Prefer using props and events for parent-child communication.</p>
+  <p class="tip">Use `$parent` and `$children` sparingly - they mostly serve as an escape-hatch. Prefer using props and events for parent-child communication.</p>
 
 ### mixins