Improve the android onboarding messages (#25353)

Summary:
When I installed React Native and loaded it up in the emulator, I wasn't really sure what the menu button was. I clicked around through the default emulator for advice but couldn't find it. So, instead this version now tells you directly what the key commands are.

Because it needs to show  both<key>ctrl</key> and <key>cmd</key> (depending on dev's OS) I opted to include both and felt like it needed spaces around the `+`. So, I made that consistent everywhere.

## Test Plan

n/a

## Changelog

[Android] [Fixed] - Improves the initial copy for creating a new RN project on android
Pull Request resolved: #25353

Differential Revision: D15956358

Pulled By: mdvacca

fbshipit-source-id: aa320e30da53e6ba35f879f57740777bdee26618

Libraries/NewAppScreen/components/DebugInstructions.js

@@ -20,14 +20,14 @@ const styles = StyleSheet.create({
 const DebugInstructions = Platform.select({
   ios: () => (
     <Text>
-      Press <Text style={styles.highlight}>Cmd+D</Text> in the simulator or{' '}
+      Press <Text style={styles.highlight}>Cmd + D</Text> in the simulator or{' '}
       <Text style={styles.highlight}>Shake</Text> your device to open the React
       Native debug menu.
     </Text>
   ),
   default: () => (
     <Text>
-      Press <Text style={styles.highlight}>menu button</Text> or{' '}
+      Press <Text style={styles.highlight}>Cmd or Ctrl + M</Text> or{' '}
       <Text style={styles.highlight}>Shake</Text> your device to open the React
       Native debug menu.
     </Text>

Libraries/NewAppScreen/components/ReloadInstructions.js

@@ -20,7 +20,7 @@ const styles = StyleSheet.create({
 const ReloadInstructions = Platform.select({
   ios: () => (
     <Text>
-      Press <Text style={styles.highlight}>Cmd+R</Text> in the simulator to
+      Press <Text style={styles.highlight}>Cmd + R</Text> in the simulator to
       reload your app's code.
     </Text>
   ),