pub fn finish(&mut self) {
		let keys = self.ignores.keys().cloned().collect::<Vec<_>>();
		for key in keys {
			if let Some(ignore) = self.ignores.get_mut(&key) {
				ignore.builder = None;
			}
		}
	}
Deletes the internal builder, to save memory.

This makes it impossible to add new ignore files without re-compiling the whole set.
crates/ignore-files/src/filter.rs