JSR: Improve documentation of public symbols

[csvn]

This issue is related to #3597, and tracks progress of documentation of public symbols.

At the time of the creation of this issue, this is the percentage of documented symbols for all packages under the @fresh scope on JSR:

• @fresh/build-id: 0% - ⛔
• @fresh/core: 44% - ⚠️
• @fresh/examples: 0% - ⛔
• @fresh/init: 100% - ✅
• @fresh/plugin-tailwind: 0% - ⛔
• @fresh/plugin-tailwind-v3: 0% - ⛔
• @fresh/plugin-vite: 0% - ⛔
• @fresh/update: 100% - ✅

I think it would be a good goal to aim for at least 80% to assuage JSR, but being closer to 100% documentation of public symbols would be even better. Not every exported type needs large text or examples, and a small description can often be helpful for users to learn the framework.

Progress

Tracking progress of packages with >80% documented public symbols.

• [ ] @fresh/build-id
• [ ] @fresh/core
• [x] @fresh/examples: #3603
• [x] @fresh/init
• [ ] @fresh/plugin-tailwind
• [ ] @fresh/plugin-tailwind-v3
• [x] @fresh/plugin-vite: #3604
• [x] @fresh/update