Improve clarity in participant and speaker selection documentation

[sakthijaw]

Description of Changes

This Pull Request improves clarity and readability in the participant and speaker selection documentation.
The changes focus on simplifying wording, improving sentence structure, and replacing HTML entities
with standard Markdown punctuation for better readability. No functional or policy changes are included.

Related Issue

Related to issue #242

Type of Change

Please check the appropriate box that describes your PR:

-[x] ✨ Content Enhancement — Updates or improves existing content

Additional Notes (Optional)

These changes are documentation-only and do not affect any functionality or recommendations.

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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