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
```
The direct reason for this is to fix CI on windows, which seems to fail
for some reason after we fixed the watcher-selection logic which (I
think) changed the tests behavior to use notify rather than client.
But this patch seems to make sense in general -- file watching is
notoriously finicky, so controlling it explicitly leads to less fragile
tests.
