docs: improve formatting in 'How to Contribute' (fixes #399)

[Amitjoiya]

Description of Changes

Related Issue

Type of Change

Please check the appropriate box that describes your PR:

• 🐛 Bug Fix — Fixes a documented issue or incorrect behavior
• ✨ Content Enhancement — Updates or improves existing content
• ✍️ New Content — Adds new chapters, examples, or significant sections
• 🛠️ Other — Please describe in the Description of Changes section

Additional Notes (Optional)

Checklist

• I have searched open pull requests to avoid duplicates.
• I have built the book locally using the build instructions and verified my changes work as expected.
• I have written clear, conventional commit messages, as per the Pull Request Guidelines.

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[Amitjoiya]

Hi, I have submitted this PR for review as part of GSoC contributions. Please take a look whenever convenient. Thanks! 😊

[Amitjoiya]

This contribution was made during my open-source preparation for GSoC and is now also being included as a pre-contribution for GSSoC 2025.