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/hir-def/src/macro_expansion_tests.rs

@@ -179,7 +179,7 @@ pub fn identity_when_valid(_attr: TokenStream, item: TokenStream) -> TokenStream
             if tree {
                 let tree = format!("{:#?}", parse.syntax_node())
                     .split_inclusive('\n')
-                    .map(|line| format!("// {}", line))
+                    .map(|line| format!("// {line}"))
                     .collect::<String>();
                 format_to!(expn_text, "\n{}", tree)
             }