Shorten `<Foo as Bar>::quux` to `Foo::quux`

I want to use `disqualified` to display system names while stepping. `system.name()` is the fully qualified name, which is unreasonably verbose. `ShortName::from(&*system.name())` helps a lot, but it leaves some system names that could be shortened further.

For example:

```rs
// Before:
Pipe(::progress, <>::progress as ProgressReturningSystem, Res) -> Progress)>>::track_progress>::{{closure}})

// After:
Pipe(HealthConfig::progress, HealthConfig::progress::track_progress>::{{closure}})
```

This probably applies to type names as well.