- Removes closures and function calls for types that implement default:
```rust
// Change
let _my_str = get_str().unwrap_or(String::new);
// To
let _my_str = get_str().unwrap_or_default();
```
- Uses the `.cloned()/.copied()` methods where possible
- Use function pointer instead of simple closure
May improve performace, as closures generate more code, and this might
unlock some inlining opportunities.
According to its benchmarks, it's almost 2x faster than
unicode_segmentation. It doesn't appear to make a visible
difference to `time cat bigfile`, but I'll take anything
that gives more headroom for such little effort of switching.
