Fix typo in docs
Summary: Pull Request resolved:
@@ -1278,7 +1278,7 @@ If you need to retain a specific query outside of the components lifecycle, you
```javascript
// Retain query; this will prevent the data for this query and
-// variables from being gabrage collected by Relay
+// variables from being garbage collected by Relay
const disposable = environment.retain(queryDescriptor);
// Disposing of the disposable will release the data for this query
