@rangojs/router 0.34.0

Changed: a hover prefetch skips prefetch: false work again; mark a loader or loading() prefetch: "intent" to run it on hover (#1373)

Before (0.33.0 to 0.33.2). A hover prefetch, and useRouter().prefetch(),
ran every loader(Def, { prefetch: false }) and the work behind every
loading(fallback, { prefetch: false }). A pointer passing over a list of
links ran the expensive loader once per link, and an app could not keep a
loader out of hovers while still prefetching the rest of the page.

Now. prefetch: false keeps the work out of every prefetch, hovers
included: the click that adopts a hover's prefetch shows the fallback and
sends one follow-up request for it, as after a viewport prefetch. The new
value prefetch: "intent" keeps the work out of viewport and render
prefetches only; a hover or useRouter().prefetch() runs it.

// Before: a hover ran ReviewsLoader.
loader(ReviewsLoader, { prefetch: false }),

// Now: a hover skips it; to run it on hover, mark it "intent".
loader(ReviewsLoader, { prefetch: "intent" }),
loading(<OrdersSkeleton />, { prefetch: "intent" }),

Request	unflagged	prefetch: false	prefetch: "intent"
Document, navigation	runs	runs	runs
Viewport, render (X-Rango-Prefetch: 1)	runs	skipped, filled at click	skipped, filled at click
Hover, useRouter().prefetch() (X-Rango-Prefetch: intent)	runs	skipped, filled at click	runs, no fill
A hover over a link already cached or in flight	as cached	as cached	as cached

• A route whose flags are all "intent" answers a hover's prefetch like a
  navigation: no private, no-cache, no Vary: X-Rango-Prefetch, no source
  scope, and its click sends nothing. Any false flag keeps the response
  deferring and page-only.
• "intent" works wherever false does: loader() and loading() in
  urls(), loader() in clientUrls() and inside intercept(). A loader
  marked "intent" cannot call ctx.rendered(), as with false.
• loader() and loading() now reject any other value with
  prefetch must be a boolean or "intent".
• Middleware that skips side effects in prefetches should test for the
  presence of X-Rango-Prefetch, not for === "1": a hover's prefetch sends
  intent and runs every loader not marked false.
• In tests, serveShellRequest(router, url, { partial: { prefetch: true }, headers: { "X-Rango-Prefetch": "intent" } }) serves a hover's prefetch.

Fixed: a link inside an open intercept to another item of its route opens it in the intercept (#1372)

Before. From an open intercept (/item/2 over /list), a link,
router.push or router.replace to another item of the same intercepted
route (/item/1) rendered the item's full page.

Now. The item opens in the intercept over the same page, with the URL
updated, and when() sees the page under the intercept as from, as the
intercept skill documents. Back steps through the items, then closes the
intercept. Links to routes with no intercept from that page, and reloads,
still render the full page. A navigation from inside an open intercept always
fetches: it does not reuse the history cache or a prefetch.