fix: added quotes for run instructions

[hendricjabs]

Summary:

When initializing a project in a folder with spaces in the name, the commandline output showed a command which is not working for these folders. In general it is not recommended to create folders with spaces but in a Windows Environment it is quite common e.g. if the username is "John Doe" and you want to initialize a react-native project in a subfolder of the home directory.

To provide a working command id added quotes around the projectDir variable, so the command can be Copy & Pasted.

Test Plan:

1. Create a directory with spaces in the name: mkdir "my repositories"
2. Switch to this directory cd "my repositories"
3. Run react-native init testproject
4. Before this change the following output was generated:
   [...]

Run instructions for iOS:
   • cd /home/johndoe/my repositories/testproject && npx react-native run-ios
   - or -
   • Open testproject/ios/testproject.xcodeproj in Xcode or run "xed -b ios"
   • Hit the Run button

 Run instructions for Android:
   • Have an Android emulator running (quickest way to get started), or a device connected.
   • cd /home/johndoe/my repositories/testproject && npx react-native run-android

5. Copy & Paste the command and run it cd /home/johndoe/my repositories/testproject && npx react-native run-android
6. Following error message occurs: -bash: cd: too many arguments

With this Pull Request the project directory is surrounded by quotes and a copy & paste of the command will work.

[grabbou]

Thanks for the PR! This makes a lot of sense and we have recently fixed a similar issue related to this!