fix typo - missing 'new' keyword

Summary:
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Fix typo in the documentation - a missing 'new' keyboard

[ DOCS ] [ BUGFIX ] [Animations.md] - Fix typo - missing 'new' keyword
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  CATEGORY
[----------]        TYPE
[ CLI      ]   [-------------]      LOCATION
[ DOCS     ]   [ BREAKING    ]   [-------------]
[ GENERAl  ]   [ BUGFIX      ]   [-{Component}-]
[ INTERNAL ]   [ ENHANCEMENT ]   [ {File}      ]
[ IOS      ]   [ FEATURE     ]   [ {Directory} ]   |-----------|
[ ANDROID  ]   [ MINOR       ]   [ {Framework} ] - | {Message} |
[----------]   [-------------]   [-------------]   |-----------|

[CATEGORY] [TYPE] [LOCATION] - MESSAGE

 EXAMPLES:

 [IOS] [BREAKING] [FlatList] - Change a thing that breaks other things
 [ANDROID] [BUGFIX] [TextInput] - Did a thing to TextInput
 [CLI] [FEATURE] [local-cli/info/info.js] - CLI easier to do things with
 [DOCS] [BUGFIX] [GettingStarted.md] - Accidentally a thing/word
 [GENERAL] [ENHANCEMENT] [Yoga] - Added new yoga thing/position
 [INTERNAL] [FEATURE] [./scripts] - Added thing to script that nobody will see
-->
Closes https://github.com/facebook/react-native/pull/16379

Differential Revision: D6067964

Pulled By: hramos

fbshipit-source-id: 8bd47aad252e9baa69cff7f878adfedfd94a5f55

docs/Animations.md

@@ -154,7 +154,7 @@ There are some cases where an animated value needs to invert another animated va
 An example is inverting a scale (2x --> 0.5x):
 
 ```javascript
-const a = Animated.Value(1);
+const a = new Animated.Value(1);
 const b = Animated.divide(1, a);
 
 Animated.spring(a, {