rust-lang#120675 introduced a new mechanism to declare intrinsics
which will potentially replace the rust-intrinsic ABI.

The new mechanism introduces a placeholder body and mark the intrinsic
with #[rustc_intrinsic_must_be_overridden].
In practice, this means that backends should not generate code for the
placeholder, and shim the intrinsic.
The new annotation is an internal compiler implementation,
and it doesn't need to be exposed to StableMIR users.

In this PR, intrinsics marked with `rustc_intrinsic_must_be_overridden`
are handled the same way as intrinsics that do not have a body.

I didn't find `crt-static` at first (for `x86_64-unknown-linux-gnu`),
because it was put at the bottom the large and otherwise sorted list.

Fully sort the list before we print it.

Note that `llvm_target_features` starts out sorted and does not need to
be sorted an extra time.

This excludes casting, which needs more tests.

Add a spot that was missed in
<rust-lang#121997>.

Const eval negation was added. This test is now covered by Miri tests,
and merged into an existing UI test.

Fixes <rust-lang#124583>

These changes bring it closer to other standard library documentation
and, in particular, `std::fs::canonicalize`, which it will often be
compared with.

* Add `# Platform-specific behavior` section, with content moved from
  Examples section.
* Create `# Errors` section.
* Phrase error description to allow future platforms to have new
  syntactic errors, rather than only emptiness.
* Add missing commas.
* Indent example code 4 spaces.

…rister

rustc_span: Add conveniences for working with span formats

This is the refactoring part of rust-lang#125017.

…li-obk

Unify intrinsics body handling in StableMIR

rust-lang#120675 introduced a new mechanism to declare intrinsics which will potentially replace the rust-intrinsic ABI.

The new mechanism introduces a placeholder body and mark the intrinsic with `#[rustc_intrinsic_must_be_overridden]`.
In practice, this means that a backend should not generate code for the placeholder, and shim the intrinsic.
The new annotation is an internal compiler implementation, and it doesn't need to be exposed to StableMIR users.

In this PR, we unify the interface for intrinsics marked with `rustc_intrinsic_must_be_overridden` and intrinsics that do not have a body.

Fixes rust-lang/project-stable-mir#79

r? ``@oli-obk``

cc: ``@momvart``

…r=Amanieu

Add `f16` and `f128` inline ASM support for `x86` and `x86-64`

This PR adds `f16` and `f128` input and output support to inline ASM on `x86` and `x86-64`. `f16` vector sizes are taken from [here](https://www.intel.com/content/www/us/en/docs/intrinsics-guide/index.html).

Relevant issue: rust-lang#125398
Tracking issue: rust-lang#116909

``@rustbot`` label +F-f16_and_f128

 Also sort `crt-static` in `--print target-features` output

I didn't find `crt-static` at first (for `x86_64-unknown-linux-gnu`), because it was put at the bottom of the large and otherwise sorted list.

Fully sort the list before we print it.

Note that `llvm_target_features` starts out and remains sorted and does not need to be sorted an extra time.

On my machine the diff is just:

```diff
$ diff -u /tmp/before2.txt /tmp/after2.txt
--- /tmp/before2.txt    2024-06-13 20:40:27.091636592 +0200
+++ /tmp/after2.txt     2024-06-13 20:39:54.584894891 +0200
``@@`` -20,6 +20,7 ``@@``
     bmi1                            - Support BMI instructions.
     bmi2                            - Support BMI2 instructions.
     cmpxchg16b                      - 64-bit with cmpxchg16b (this is true for most x86-64 chips, but not the first AMD chips).
+    crt-static                      - Enables C Run-time Libraries to be statically linked.
     ermsb                           - REP MOVS/STOS are fast.
     f16c                            - Support 16-bit floating point conversion instructions.
     fma                             - Enable three-operand fused multiple-add.
``@@`` -49,7 +50,6 ``@@``
     xsavec                          - Support xsavec instructions.
     xsaveopt                        - Support xsaveopt instructions.
     xsaves                          - Support xsaves instructions.
-    crt-static                      - Enables C Run-time Libraries to be statically linked.

 Code-generation features supported by LLVM for this target:
     16bit-mode                      - 16-bit mode (i8086).
```

I couldn't find a ui test that tested this output. Let's see if CI finds a regression tests.

Polish `std::path::absolute` documentation.

These changes bring it closer to other standard library documentation and, in particular, `std::fs::canonicalize`, which it will often be compared with.

* Add `# Platform-specific behavior` section, with content moved from Examples section.
* Create `# Errors` section.
* Phrase error description to allow future platforms to have new syntactic errors, rather than only emptiness.
* Add missing commas.
* Indent example code 4 spaces.

…lfJung

Add `f16` and `f128` const eval for binary and unary operationations

Add const evaluation and Miri support for f16 and f128, including unary and binary operations. Casts are not yet included.

Fixes rust-lang#124583

r? ``@RalfJung``

End support for Python 3.8 in tidy

Python 3.8 will reach its end of support in October 2024. You can find more details [here](https://devguide.python.org/versions/).

### NixOS

NixOS has already discontinued provide Python 3.8. For more information, visit their [package search page](https://search.nixos.org/packages?channel=24.05&from=0&size=50&sort=relevance&type=packages&query=python38).

### Debian

- **Debian 11 (Bullseye)**: The default Python version is 3.9. More information is available [here](https://packages.debian.org/bullseye/python3).
- **Debian 10 (Buster) (EOL 2024-10)**: The default Python version is 3.7. Details can be found [here](https://packages.debian.org/buster/python3).

### Ubuntu

- **Ubuntu 20.04 'Focal Fossa' (LTS)**: The default Python version is 3.8.2. However, Python 3.9 is also available. You can find more information on these packages [here](https://packages.ubuntu.com/focal/python3) and [here](https://packages.ubuntu.com/focal/python3.9).
- **Ubuntu 22.04 'Jammy Jellyfish' (LTS)**: The default Python version is 3.10.6. More details can be found [here](https://packages.ubuntu.com/jammy/python3).

…an68

Use `std::path::absolute` in bootstrap

`std::path::absolute` is now stable in 1.79 so we can get rid of the copy-pasted version.

.mailmap: Associate both my work and my private email with me

Mainly so that 73 + 60 is summed to 133 on the [thanks](https://thanks.rust-lang.org/rust/all-time/) page.