Added Defer for better performance and corrected some misspelling

[aniket6508]

Added defer keyword in Script Tag to enhance performance and also corrected spelling "link" to "like" at the place holder

[malivinayak]

Thank you for your efforts Your branch is behind the latest changes placeholder issue is already fixed at #28

defer keyword is not strictly needed here

You can contribute on some real issue or contributions are welcome at

• https://github.com/malivinayak/Markdown/
• https://github.com/malivinayak/Multi-Programming