docs: add JSDoc descriptions

[JoshuaKGoldberg]

PR Checklist

• Addresses an existing open issue: fixes 📝 Documentation: Add JSDoc descriptions to public APIs. #22
• That issue was marked as status: accepting prs
• Steps in CONTRIBUTING.md were taken

Overview

"Informativity" is a word!

[codecov]

Codecov Report

Merging #23 (52396f7) into main (9c1fd52) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##              main       #23   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            1         1           
  Lines           16        16           
  Branches         5         5           
=========================================
  Hits            16        16           

Impacted Files	Coverage Δ
src/index.ts	100.00% <ø> (ø)

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[JoshuaKGoldberg]

@all-contributors please add @JoshuaKGoldberg for doc.

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[allcontributors]

@JoshuaKGoldberg

I've put up a pull request to add @JoshuaKGoldberg! 🎉

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