ci: update nightly version to 2025-10-12

[Darksonn]

See #7653

This will undo #7652

[ADD-SP]

I pushed a commit to see if this fix the test failure.

[Darksonn]

I don't really understand where this failure comes from. Using an int is the new format, and this should be on the 2025-10-12 nightly, right?

Run cargo nextest run -Zbuild-std --target target-specs/i686-unknown-linux-gnu.json -p tokio --features $TOKIO_STABLE_FEATURES,taskdump
  error: error deserializing custom target JSON for `i686-unknown-linux-gnu`
    ╭─[47:28]
 46 │   ],
 47 │   "target-pointer-width": 32
    ·                            ▲
    ·                            ╰── invalid type: integer `32`, expected a string
 48 │ }
    ╰────

[ADD-SP]

Emm, this looks strange, the rust-lang/rust#144443 is still there.

[ADD-SP]

Switching back to cargo test instead of cargo nextest will fix this issue.

Run cargo nextest run -Zbuild-std --target target-specs/i686-unknown-linux-gnu.json -p tokio --features $TOKIO_STABLE_FEATURES,taskdump
  error: error deserializing custom target JSON for `i686-unknown-linux-gnu`
    ╭─[47:28]
 46 │   ],
 47 │   "target-pointer-width": 32
    ·                            ▲
    ·                            ╰── invalid type: integer `32`, expected a string
 48 │ }
    ╰────

[ADD-SP]

Revert 96647b5 because of a suspicious miscompilation, see #7671 (comment).

[Darksonn]

I wonder if this mismatch is due to nextest?

[Darksonn]

Let's update non-docs checks separately.

[Darksonn]

They were really quick to fix the nextest bug, so let's do the update after all: nextest-rs/nextest#2653

Thanks! @sunshowers

[Darksonn]

@taiki-e Do you know why install-action is still installing v0.9.105 when v0.9.106 has been available on github releases for some time?

[taiki-e]

I'm out for work, so I currently can't create the release.

I plan to go home in 2 hours, but there is an update in the main branch, so you can also use it. (The update work is automated, so the main branch is generally up-to-date or up to three hours late, but the owner's involvement is required to create a release.)

[taiki-e]

Created the new release of install-action which contains the latest version of nextest.

[Darksonn]

Thanks!