Merge pull request #231 from br0p0p/patch-1

Fix missing word

react-docs/source/cache-updates.md

@@ -85,7 +85,7 @@ In some cases, just using `dataIdFromObject` is not enough for your application
 
 <h3 id="refetchQueries">`refetchQueries`</h3>
 
-`refetchQueries` is the simplest way of updating the cache. With `refetchQueries` you can specify one or more queries that you want to run after a mutation completed in order to refetch the parts of the store that may have been affected by the mutation:
+`refetchQueries` is the simplest way of updating the cache. With `refetchQueries` you can specify one or more queries that you want to run after a mutation is completed in order to refetch the parts of the store that may have been affected by the mutation:
 
 ```javascript
 mutate({