Update SectionList.js

Summary:
minor spelling error fix

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- [ Found this small spelling error while reading thought of reporting it  ] Explain the **motivation** for making this change.
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[1]: https://medium.com/martinkonicek/what-is-a-test-plan-8bfc840ec171#.y9lcuqqi9
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Closes https://github.com/facebook/react-native/pull/14273

Differential Revision: D5160964

Pulled By: hramos

fbshipit-source-id: 3142cc511476e8b494576b8e31faf43eb97b40c5

Libraries/Lists/SectionList.js

@@ -240,7 +240,7 @@ type DefaultProps = typeof defaultProps;
  *   (e.g. `extraData`) that is not `===` after updates, otherwise your UI may not update on
  *   changes. This includes the `data` prop and parent component state.
  * - In order to constrain memory and enable smooth scrolling, content is rendered asynchronously
- *   offscreen. This means it's possible to scroll faster than the fill rate ands momentarily see
+ *   offscreen. This means it's possible to scroll faster than the fill rate and momentarily see
  *   blank content. This is a tradeoff that can be adjusted to suit the needs of each application,
  *   and we are working on improving it behind the scenes.
  * - By default, the list looks for a `key` prop on each item and uses that for the React key.