Broken Links in README.md

[INFCode]

Thanks for collecting helpful links and projects to learn about Moonbit! I noticed that several links in README.md are no longer accessible, returning 404 errors. Here's a list of those broken links, at least on my side:

• The Up and Running with MoonBit tutorial.
• The create a Pull Request template.
• The Fibonacci benchmark.
• The MoonBit's FFI document.
• All links in the Examples section except Tetris Game and MoonUI.
• The Build system tutorial.

This may hinder users from exploring the awesome projects listed here. It would be helpful to audit and remove broken links or update them if possible.