@types/bun: More JSDoc improvements for docgen

[alii]

What does this PR do?

Improves some of the JSDoc defined in bun-types

• Documentation or TypeScript types (it's okay to leave the rest blank in this case)
• Code changes

[robobun]

^{Updated 11:50 AM PT - Apr 17th, 2025}

❌ @alii, your commit 5322ff5 has 1 failures in Build #15081:

• test/js/web/fetch/fetch.test.ts - 1 failing on 🍎 14 aarch64

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🧪   try this PR locally:

bunx bun-pr 19024