Update Rust to 1.91 (#626)

mlafeldt · web-flow · commit 6cefb40599b4 · 2025-11-14T14:25:21.000+01:00
https://blog.rust-lang.org/2025/10/30/Rust-1.91.0/
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
@@ -1,3 +1,3 @@
 [toolchain]
-channel = "1.90"
+channel = "1.91"
 components = ["rustfmt", "clippy"]
