Rust 1.88.0 (#85)

* Rust 1.88.0

* nix flake update

* cargo upgrade

* lint

all `uninlined_format_args` related
@see https://rust-lang.github.io/rust-clippy/master/index.html#uninlined_format_args

src/widgets/countdown.rs

@@ -319,7 +319,7 @@ fn human_days_diff(a: &OffsetDateTime, b: &OffsetDateTime) -> String {
     match days_diff {
         0 => "today".to_owned(),
         1 => "tomorrow".to_owned(),
-        n => format!("+{}days", n),
+        n => format!("+{n}days"),
     }
 }