[4.0.0-beta4] hx-preload doesn't support "intersect" or "revealed"

I hope there’s an aggressive way to prefetch links on mobile **when a link enters the viewport**.

Google has also been promoting the [Speculation Rules API](https://developer.chrome.com/docs/web-platform/implementing-speculation-rules) lately, which allows prefetching and prerendering pages in the background. So I was hoping HTMX would have something similar to it.

While HTMX 4 documents that “[_Preload can listen to any event name supported by htmx trigger specs._](https://four.htmx.org/extensions/hx-preload#hx-preloadcustom-event-name)", it doesn’t support `intersect` or `revealed` (because they aren’t regular events?). In that case, “supported by htmx trigger specs” sounds ambiguous.