Automatic toolchain upgrade to nightly-2025-09-08 (#4350)

Update Rust toolchain from nightly-2025-09-07 to nightly-2025-09-08
without any other source changes.

Co-authored-by: tautschnig <[email protected]>
Co-authored-by: Zyad Hassan <[email protected]>

Author: 3 people

rust-toolchain.toml

@@ -2,5 +2,5 @@
 # SPDX-License-Identifier: Apache-2.0 OR MIT
 
 [toolchain]
-channel = "nightly-2025-09-07"
+channel = "nightly-2025-09-08"
 components = ["llvm-tools", "rustc-dev", "rust-src", "rustfmt"]