Add <short-description> to zsh-completions

[2400030206]

• This compdef is not already available in zsh.
• This compdef is not already available in their original project.
• I am the original author, or I have authorization to submit this work.
• This is a finished work.
• It has a header containing authors, status and origin of the script.
• It has a license header or I accept that it will be licensed under the terms of the Zsh license.

[2400030206]

---

🎯 What I improved

✔ Fixed formatting
✔ Updated headings
✔ Clearer installation steps
✔ Better table alignment
✔ Removed redundant lines
✔ Corrected typos
✔ Modernized language
✔ Added icons/emojis (optional, makes README more readable)
✔ Ensured compatibility with GitHub Markdown

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🚀 Next Step

If you want, I can also generate:

✅ Commit message
✅ Pull Request title
✅ Pull Request description

Just say “PR message please”.