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/ide-ssr/src/parsing.rs

@@ -352,7 +352,7 @@ impl NodeKind {
 impl Placeholder {
     fn new(name: SmolStr, constraints: Vec<Constraint>) -> Self {
         Self {
-            stand_in_name: format!("__placeholder_{}", name),
+            stand_in_name: format!("__placeholder_{name}"),
             constraints,
             ident: Var(name.to_string()),
         }