Font Fallback not working for at least `汉` on Windows

Nobody has claimed this yet.

The font family returned by fontique for the `Hani` script is `Yu Gothic UI` on Windows, which does not have the character `汉`. The character is in `Microsoft YaHei UI`, which is not returned at all.

Reproduction:

```rust
use fontique::{Collection, FallbackKey, Script, SourceCache};

let mut collection = Collection::default();
let mut source_cache = SourceCache::default();
let family_ids: Vec<_> = collection
.fallback_families(FallbackKey::new(Script::from_bytes(*b"Hani"), None))
.collect();
let family_names: Vec<_> = family_ids
.iter()
.map(|&id| collection.family_name(id).unwrap().to_owned())
.collect();

println!("fallback families: {family_names:?}");

let family_id = family_ids[0];
let family_name = collection.family_name(family_id).unwrap().to_owned();
let family = collection.family(family_id).unwrap();
let font = family.default_font().unwrap();
let data = font.load(Some(&mut source_cache)).unwrap();
let charmap = font.charmap_index().charmap(data.as_ref()).unwrap();

println!("{family_name}: 汉 -> {:?}", charmap.map('汉'));
```

The problematic line seems to be here, which doesn't contain enough characters for more coverage:
https://github.com/linebender/parley/blob/8294d3e50d48e14dbd8be7982d8d4548996ef561/fontique/src/script.rs#L112

though apparently for DirectWrite only a single font is queried anyway, so it wouldn't be the only thing that needs to be fixed.
https://github.com/linebender/parley/blob/8294d3e50d48e14dbd8be7982d8d4548996ef561/fontique/src/backend/dwrite.rs#L200

Start in fontique/src/script.rs at the fallback character coverage and in fontique/src/backend/dwrite.rs at the DirectWrite font query. Reproduce the Windows case with the provided Rust snippet, then inspect the returned families and charmap result for 汉. Done means the fallback path returns a font whose charmap contains 汉, including the DirectWrite path.

Written by the indexing model from the issue text.