Inline all format arguments where possible

This makes code more readale and concise,
moving all format arguments like `format!("{}", foo)`
into the more compact `format!("{foo}")` form.

The change was automatically created with, so there are far less change
of an accidental typo.

```
cargo clippy --fix -- -A clippy::all -W clippy::uninlined_format_args
```

crates/cfg/src/cfg_expr.rs

@@ -44,7 +44,7 @@ impl fmt::Display for CfgAtom {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             CfgAtom::Flag(name) => name.fmt(f),
-            CfgAtom::KeyValue { key, value } => write!(f, "{} = {:?}", key, value),
+            CfgAtom::KeyValue { key, value } => write!(f, "{key} = {value:?}"),
         }
     }
 }