docs: harmonize grammar and style across book

[adulau]

Motivation

• Normalize grammar, capitalization, and phrasing across the book so the documentation reads consistently in American English.
• Improve clarity of contributor-facing guidance and chapter introductions to reduce ambiguity for new contributors and translators.
• Make common UI/procedural pages and examples easier to follow by standardizing terminology and formatting.

Description

• Edited top-level landing and navigation files including README.md, SUMMARY.md, and CONTRIBUTING.md to standardize tone and capitalization.
• Rewrote and clarified multiple chapter introductions and procedural pages such as USAGE.md, create-event-report/README.md, delegation/README.md, connectors/README.md, pymisp/README.md, updating-python/README.md, get-your-instance/README.md, modules/README.md, noticelists/README.md, and warninglists/README.md.
• Cleaned glossary and style guidance in GLOSSARY.md, book-convention/README.md, and translation/README.md to align terminology and translation guidance.
• Performed whitespace and formatting cleanups (tabs replaced, trailing spaces removed) across the edited files to improve diffs and build hygiene.

Testing

• Ran git diff --check to detect whitespace and patch issues and fixed reported problems, which returned no errors.
• Ran a Python script that verified there are no trailing whitespace characters or tab characters in the reviewed files (checked files listed in the PR), and it reported OK.
• Reviewed diffs for the edited files (README.md, SUMMARY.md, CONTRIBUTING.md, GLOSSARY.md, USAGE.md, chapter README files) to ensure wording and formatting changes are consistent and do not alter technical instructions; no regressions were found.
• All automated checks referenced above passed.

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Codex Task