…result" setting

…rom-raw-parts, r=m-ou-se,the8472

Stabilize `nonnull_slice_from_raw_parts`

FCP is done: rust-lang#71941 (comment)
Note that this doesn't const-stabilize `NonNull::slice_from_raw_parts` as `slice_from_raw_parts_mut` isn't const-stabilized yet. Given rust-lang#67456 and rust-lang#57349, it's not likely available soon, meanwhile, stabilizing only the feature makes some sense, I think.

Closes rust-lang#71941

Follow C-RW-VALUE in std::io::Cursor example

rustc-dev-guide says to do this:

r? `@steveklabnik`

…tch, r=GuillaumeGomez

rustdoc: Fix LinkReplacer link matching

It currently just uses the first link with the same href which might not necessarily be the matching one.

This fixes replacements when there are several links to the same item but with different text (e.g. `[X] and [struct@X]`). It also fixes replacements in summaries since those use a links list with empty hrefs, so currently all links would always match the first link by href but then not match its text. This could also lead to a panic in the `original_lext[1..len() - 1]` part when the first link only has a single character, which is why the new code uses `.get(..)` instead.

…=Nilstrieb

Use an IndexVec to debug fingerprints.

Uncontroversial part of rust-lang#109050

…stion, r=compiler-errors

fix type suggestions in match arms

fix rust-lang#109586

…ing, r=notriddle

Fix "Directly go to item in search if there is only one result" setting

Part of rust-lang#66181.

The setting was actually broken, so I fixed it when I added the GUI test.

r? `@notriddle`

…-obl, r=oli-obk

Don't elaborate non-obligations into obligations

It's suspicious to elaborate a `PolyTraitRef` or `Predicate` into an `Obligation`, since the former does not have a param-env associated with it, but the latter does. This is a footgun that, while not being misused *currently* in the compiler, easily could be misused by someone less familiar with the elaborator's inner workings.

This PR just changes the API -- ideally, the elaborator wouldn't even have to deal with obligations if we're not elaborating obligations, but that would require a bit more abstraction than I could be bothered with today.