Add syntax highlighting to block codes in main README

[Neblinus]

Summary

Added syntax highlighting to code blocks in the repo's main README, just for providing nicer docs.

Type of change

• Minor changes or tweaks (quality of life stuff)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Notes for reviewer

Thanks for all your work and contributions to OSS.