Update Images.md

Summary:
Remove redundant `\`` mark

Thanks for submitting a PR! Please read these instructions carefully:

- [x] Explain the **motivation** for making this change.
- [x] Provide a **test plan** demonstrating that the code is solid.
- [x] Match the **code formatting** of the rest of the codebase.
- [x] Target the `master` branch, NOT a "stable" branch.

This PR fixes Documentation typo.

No need for test.
Closes https://github.com/facebook/react-native/pull/13228

Differential Revision: D4810457

Pulled By: hramos

fbshipit-source-id: 5c475a5d8b51d4a926e0fc737e2a12805e3bf70b

docs/Images.md

@@ -113,7 +113,7 @@ and the load is considered to have failed.
 ```javascript
 <Image source={{uri: 'https://facebook.github.io/react/img/logo_og.png', cache: 'only-if-cached'}}
        style={{width: 400, height: 400}} />
-````
+```
 
 ## Local Filesystem Images