Tracking issue for release notes of #137951: Blog post entry for i586-pc-windows-msvc removal

[rustbot]

This issue tracks the release notes text for #137951.

cc @Noratrieb -- original issue/PR authors and assignees for drafting text

See the forge.rust-lang.org chapter about release notes for an overview of how the release team makes use of these tracking issues.

Release notes text

This section should be edited to specify the correct category(s) for the change, with succinct description(s) of what changed. Some things worth considering:

• Does this need an additional compat notes section?
• Was this a libs stabilization that should have additional headers to list new APIs under Stabilized APIs and Const Stabilized APIs?

nothing: REMOVE THIS!!

Tip

Use the previous releases for inspiration on how to write the release notes text and which categories to pick.

Release blog section

If this change is notable enough for inclusion in the blog post then this section should be edited to contain a draft for the blog post. Otherwise leave it empty.

## Target deprecation warning for 1.87.0

The target `i586-pc-windows-msvc` will be removed in the next version of Rust, 1.87.0.
This is because this target is effectively useless.
Its difference to the much more popular `i686-pc-windows-msvc` is that it does not require SSE2 instruction support, but Windows 10,
the minimum required OS version of all `windows` targets (except the `win7` targets), requires SSE2 instructions itself, so this target does not fulfill a purpose.
You can check the [Major Change Proposal](https://github.com/rust-lang/compiler-team/issues/840) for more information.

Note

If a blog post section is required the release-blog-post label should be added (@rustbot label +release-blog-post) to this issue as otherwise it may be missed by the release team.

[Mark-Simulacrum]

I think we can probably have the compat notes section too? Just noting something is coming, but seems reasonable to include in both places.

[programmerjake]

the title should be i586, not i686