fix typo - closes #13369

Summary:
We're just fixing a reported typo from the docs.

proofreading
Closes #13375

Differential Revision: D4851601

Pulled By: javache

fbshipit-source-id: b8bd4067285809dd24b6e5c9bc8fddcc8734dfd1

Libraries/Components/ScrollView/ScrollView.js

@@ -56,7 +56,7 @@ const requireNativeComponent = require('requireNativeComponent');
  *
  * On the other hand, this has a performance downside. Imagine you have a very
  * long list of items you want to display, maybe several screens worth of
- * content. Creating JS components and native views for everythign all at once,
+ * content. Creating JS components and native views for everything all at once,
  * much of which may not even be shown, will contribute to slow rendering and
  * increased memory usage.
  *