Previously, we had the `ae-forgotten-export` rule from api-extractor
disabled. This rule makes sure that everything that's referred to in the
public API is actually exported. There are more details on the rule
[here](https://api-extractor.com/pages/messages/ae-forgotten-export/),
but not exporting public API entires is bad because they're hard to
document and can't be typed/called from consumer code. For us, the big
effect is that they don't appear in our docs at all.
This diff re-enables that rule. Now, if you introduce something new to
the public API but don't export it, your build will fail.
### Change Type
- [x] `docs` — Changes to the documentation, examples, or templates.
- [x] `improvement` — Improving existing features
