Improves the copy for the new app screen (facebook#24918)

Summary:
1. Consistency with full stops  (you can see screenshots in facebook#24783 )
2. Improvements to the wording, describing what you're going to see

## Changelog

[Internal] [Fixed] - Improves the copy for the new app screen
Pull Request resolved: facebook#24918

Differential Revision: D15391421

Pulled By: cpojer

fbshipit-source-id: 2ec6d2d5bd4845c5f4c699838ae865ab4217e49e

Libraries/NewAppScreen/components/LearnMoreLinks.js

@@ -19,19 +19,18 @@ const links = [
   {
     title: 'The Basics',
     link: 'https://facebook.github.io/react-native/docs/tutorial',
-    description:
-      'Read the docs on what to do once seen how to work in React Native.',
+    description: 'Explains a Hello World for React Native.',
   },
   {
     title: 'Style',
     link: 'https://facebook.github.io/react-native/docs/style',
-    description: 'All of the core components accept a prop named style.',
+    description:
+      'Covers how to use the prop named style which controls the visuals.',
   },
   {
     title: 'Layout',
     link: 'https://facebook.github.io/react-native/docs/flexbox',
-    description:
-      'A component can specify the layout of its children using the flexbox specification.',
+    description: 'React Native uses flexbox for layout, learn how it works.',
   },
   {
     title: 'Components',

Libraries/NewAppScreen/components/ReloadInstructions.js

@@ -21,13 +21,13 @@ const ReloadInstructions = Platform.select({
   ios: () => (
     <Text>
       Press <Text style={styles.highlight}>Cmd+R</Text> in the simulator to
-      reload your app's code
+      reload your app's code.
     </Text>
   ),
   default: () => (
     <Text>
       Double tap <Text style={styles.highlight}>R</Text> on your keyboard to
-      reload your app's code
+      reload your app's code.
     </Text>
   ),
 });

template/App.js

@@ -56,8 +56,7 @@ const App = () => {
             <View style={styles.sectionContainer}>
               <Text style={styles.sectionTitle}>Learn More</Text>
               <Text style={styles.sectionDescription}>
-                Read the docs on what to do once seen how to work in React
-                Native.
+                Read the docs to discover what to do next:
               </Text>
             </View>
             <LearnMoreLinks />