Rollup of 17 pull requests

Successful merges:

 - #53030 (Updated RELEASES.md for 1.29.0)
 - #53104 (expand the documentation on the `Unpin` trait)
 - #53213 (Stabilize IP associated constants)
 - #53296 (When closure with no arguments was expected, suggest wrapping)
 - #53329 (Replace usages of ptr::offset with ptr::{add,sub}.)
 - #53363 (add individual docs to `core::num::NonZero*`)
 - #53370 (Stabilize macro_vis_matcher)
 - #53393 (Mark libserialize functions as inline)
 - #53405 (restore the page title after escaping out of a search)
 - #53452 (Change target triple used to check for lldb in build-manifest)
 - #53462 (Document Box::into_raw returns non-null ptr)
 - #53465 (Remove LinkMeta struct)
 - #53492 (update lld submodule to include RISCV patch)
 - #53496 (Fix typos found by codespell.)
 - #53521 (syntax: Optimize some literal parsing)
 - #53540 (Moved issue-53157.rs into src/test/ui/consts/const-eval/)
 - #53551 (Avoid some Place clones.)

Failed merges:

r? @ghost

Avoid some Place clones.

This is a 0.5% speedup on ripgrep.

Replace usages of ptr::offset with ptr::{add,sub}.

Rust provides these helper methods – so let's use them!

Stabilise raw_identifiers feature

* [Reference PR](https://github.com/rust-lang-nursery/reference/pull/395)
* [Book PR](https://github.com/rust-lang/book/pull/1480)
* [Rust by Example PR](https://github.com/rust-lang/rust-by-example/pull/1095)

Closes #48589.

r? @cramertj
CC @cuviper @centril

Moved issue-53157.rs into src/test/ui/consts/const-eval/

expand the documentation on the `Unpin` trait

provides an overview of the Pin API which the trait is for,
and show how it can be used in making self referencial structs

part of #49150

Document Box::into_raw returns non-null ptr

Closes  #52806.

add individual docs to `core::num::NonZero*`

syntax: Optimize some literal parsing

Currently in the `wasm-bindgen` project we have a very very large crate that's
procedurally generated, `web-sys`. To generate this crate we parse all of a
browser's WebIDL and we then generate bindings for all of the APIs contained
within.

The resulting Rust file is 18MB large (wow!) and currently takes a very long
time to compile in debug mode. On the nightly compiler a *debug* build takes 90s
for the crate to finish. I was curious what was taking so long and upon
investigating a *massive* portion of the time was spent in the `lit_token`
method of the compiler, primarily formatting strings via `format!`.

Upon some more investigation it looks like the `byte_str_lit` was allocating an
error message once per byte, causing a very large number of allocations to
happen for large literals, of which wasm-bindgen generates quite a few (some are
MB large).

This commit fixes the issue by lazily allocating the error message, only doing
so if the error message is actually needed (which should be never). As a result,
the debug mode compilation time for our `web-sys` crate decreased from 90s to
20s, a very nice improvement! (although we've still got some work to do).

Fix typos found by codespell.

update lld submodule to include RISCV patch

This pulls in one new commit, to add support for linking static RISCV
binaries, suitable for the new riscv32imac-unknown-none-elf target.
See: https://github.com/rust-lang/lld/pull/1

Remove LinkMeta struct

Fixes #53291

Change target triple used to check for lldb in build-manifest

The wrong target triple was used for lldb in build-manifest.  lldb is
only built for macOS, so update the triple to reflect that.

This is an attempt to fix bug#48168.

restore the page title after escaping out of a search

Currently if I start a search in the docs, but then hit ESC, the "Results for..." title is still there in my browser tab. This is a simple attempt to fix that. I see that there's a separate `var previousTitle = document.title` thing happening in `startSearch()`, but as far as I can tell that's only related to the back stack? I'd also appreciate feedback on the right place to declare the `titleBeforeSearch` variable.

Testing-wise, I've confirmed by hand that the tab title restores correctly after building with `./x.py doc --stage 1 src/libstd`, but nothing more involved than that. What else should I test?

Mark libserialize functions as inline

Got to thinking: "what if that big pile of tiny functions isn't inlining as it should?"
So a few `replace-regex` later the local perf run says this:
<details>

![](https://i.imgur.com/gvdJEgG.png)
</details>
Not huge, but still a win, which is interesting. Want to verify with the real perf run, but I understand there's a backlog.

I didn't notice any increase in compile time or binary sizes for rustc/libs.

Stabilize macro_vis_matcher

This PR should stabilize [macro_vis_matcher](https://github.com/rust-lang/rust/issues/41022) feature.

- [ ] "reference" book changes: https://github.com/rust-lang-nursery/reference/pull/400
- [ ] "Rust by example" book changes: https://github.com/rust-lang/rust-by-example/pull/1096
- [ ] "clippy" changes: https://github.com/rust-lang-nursery/rust-clippy/pull/3055

r? @cramertj

This is a 0.5% speedup on ripgrep.

Change `Rc::inc_{weak,strong}` to better hint optimization to LLVM

As discussed in #13018, `Rc::inc_strong` and `Rc::inc_weak` are changed to allow compositions of `clone` and `drop` to be better optimized. Almost entirely as in [this comment](https://github.com/rust-lang/rust/issues/13018#issuecomment-408642184), except that `abort` on zero is added so that a `drop(t.clone())` does not produce a zero check followed by conditional deallocation.

This is different from #21418 in that it doesn't rely on `assume`, avoiding the prohibitive compilation slowdown.

[Before and after IR](https://gist.github.com/hermord/266e55451b7fe0bb8caa6e35d17c86e1).

Currently in the `wasm-bindgen` project we have a very very large crate that's
procedurally generated, `web-sys`. To generate this crate we parse all of a
browser's WebIDL and we then generate bindings for all of the APIs contained
within.

The resulting Rust file is 18MB large (wow!) and currently takes a very long
time to compile in debug mode. On the nightly compiler a *debug* build takes 90s
for the crate to finish. I was curious what was taking so long and upon
investigating a *massive* portion of the time was spent in the `lit_token`
method of the compiler, primarily formatting strings via `format!`.

Upon some more investigation it looks like the `byte_str_lit` was allocating an
error message once per byte, causing a very large number of allocations to
happen for large literals, of which wasm-bindgen generates quite a few (some are
MB large).

This commit fixes the issue by lazily allocating the error message, only doing
so if the error message is actually needed (which should be never). As a result,
the debug mode compilation time for our `web-sys` crate decreased from 90s to
20s, a very nice improvement! (although we've still got some work to do).

When closure with no arguments was expected, suggest wrapping

Fix #49694.

Stabilize IP associated constants

Fixes #44582

Updated RELEASES.md for 1.29.0

[Rendered](https://github.com/Aaronepower/rust/blob/master/RELEASES.md)

r? @Mark-Simulacrum
cc @rust-lang/release

The Great Generics Generalisation: HIR Followup

Addresses the final comments in #48149.

r? @EddyB, but there are a few things I have yet to clean up. Making the PR now to more easily see when things break.

cc @yodaldevoid

Add the identity function as core::convert::identity

## New notes

This implements rust-lang/rfcs#2306 (see https://github.com/rust-lang/rust/issues/53500).

## Old notes (ignore this in new reviews)

Adds the identity function `fn id<T>(x: T) -> T { x }` to core::convert and the prelude.
Some motivations for why this is useful are explained in the doc tests.
Another is that using the identity function instead of `{ x }` or `|x| x` makes it clear that you intended to use an identity conversion on purpose.

The reasoning:
+ behind adding this to `convert` and not `mem` is that this is an identity *conversion*.
+ for adding this to the prelude is that it should be easy enough to use that the ease of writing your own identity function or using a closure `|x| x` doesn't overtake that.

I've separated this out into two feature gates so that the addition to the prelude can be considered and stabilized separately.

cc @bluss

Update clippy

r? @oli-obk @EddyB

try to infer linker flavor from linker name and vice versa

This is a second take on PR #50359 that implements the logic proposed in https://github.com/rust-lang/rust/pull/50359#pullrequestreview-116663121

With this change it would become possible to link `thumb*` binaries using GNU's LD on stable as `-C linker=arm-none-eabi-ld` would be enough to change both the linker and the linker flavor from their default values of `arm-none-eabi-gcc` and `gcc`.

To link `thumb*` binaries using rustc's LLD on stable `-Z linker-flavor` would need to be stabilized as `-C linker=rust-lld -Z linker-flavor=ld.lld` are both required to change the linker and the linker flavor, but this PR doesn't propose that. We would probably need some sort of stability guarantee around `rust-lld`'s name and availability to make linking with rustc's LLD truly stable.

With this change it would also be possible to link `thumb*` binaries using a system installed LLD on stable using the `-C linker=ld.lld` flag (provided that `ld.lld` is a symlink to the system installed LLD).

r? @alexcrichton

Rename CodeMap/FileMap to SourceMap/SourceFile

A first renaming for #51574