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
```
- allow appending tokens after a token, not just a node
- allow inserting delimiters (and remove them again)
- fix up `if {}` and `if` without anything following