This commit implements the following methods:
* `SystemTime::saturating_add`
* `SystemTime::saturating_sub`
* `SystemTime::saturating_duration_since`

The implementation of these methods is rather trivial, as the main logic
lies behind the constants `SystemTime::MIN` and `SystemTime::MAX`.

…ottmcm

Stabilize `alloc_layout_extra`

Tracking issue: rust-lang#55724
FCP completed in rust-lang#55724 (comment)
Closes rust-lang#55724

----

As per rust-lang#55724 (comment),
- `repeat_packed` and `extend_packed` are unchanged
- `repeat` now excludes trailing padding on the last element from the total array size
- `dangling` renamed to `dangling_ptr`
- `padding_needed_for` not stabilized, changed to accept `Alignment` instead of `usize` and moved to the `ptr_aligment_type` feature flag (tracking issue: rust-lang#102070)

Add title field to `ice.md` issue template

The `ice.yml` template has [a title field](https://github.com/rust-lang/rust/blob/d0835adc4e114eac911150b3692b830b5583223a/.github/ISSUE_TEMPLATE/ice.yaml?plain=1#L4), but the `ice.md` template doesn't.

…=fee1-dead

Underscore-prefixed bindings are explicitly allowed to be unused

Fixes rust-lang#149889

…-Simulacrum

time: Add saturating arithmetic for `SystemTime`

This commit implements the following methods:
* `SystemTime::saturating_add`
* `SystemTime::saturating_sub`
* `SystemTime::saturating_duration_since`

The implementation of these methods is rather trivial, as the main logic lies behind the constants `SystemTime::MIN` and `SystemTime::MAX`.

See also:
* Accepted ACP: rust-lang/libs-team#718
* Tracking Issue: rust-lang#151199

Change field `bit_width: usize` to `bits: u32` in type info

Follow-up rust-lang#151123 (comment). Quotes:

@Skgland:
> > I'm not sure whether we should use `usize` or `u64` here to represent the bit width.
>
> My expectation would be `u32` matching the associated `{u,i}N::BITS`[^1][^2][^3] constant that already exists on the integer types.
>
> [^1]: https://doc.rust-lang.org/std/primitive.i8.html#associatedconstant.BITS
> [^2]: https://doc.rust-lang.org/std/primitive.i128.html#associatedconstant.BITS
> [^3]: https://doc.rust-lang.org/std/primitive.usize.html#associatedconstant.BITS

@SpriteOvO:
> I found some [previous discussions](rust-lang#76492 (comment)) regarding the type of `::BITS` constant. And during the stabilization of `::BITS`, the choice of `u32` affected some ecosystem crates (rust-lang#81654), but soon after, these crates all accepted the `u32` type.
>
> So I think it makes sense to keep the type consistent with `::BITS` here. Then I'd also like to change the name from `bit_width` to `bits`, also for consistency.

r? @oli-obk

Port #[needs_allocator] to attribute parser

Tracking issue: rust-lang#131229

Ports needs_allocator attribute to the new attribute parser.
Note: this is a deprecated and feature gated attribute.

Include a link to `count_ones` in the docs for `uN::count_zeros` [docs only]

I did not update `iN` because `count_zeros` is reasonable for *negative* numbers.

Rendered:
<img width="1188" height="524" alt="image" src="https://github.com/user-attachments/assets/80ebf53c-3cde-4230-b436-d2148b07d4c8" />
<img width="1186" height="517" alt="image" src="https://github.com/user-attachments/assets/544d2ff4-ee35-44f7-8d50-65fc5f0ff3c9" />

remove trailing periods in built-in attribute gate messages

consistency, we do this for all diagnostic texts