Fix formatting and example lint after shroud->noxis rename

- cargo fmt --all: shorter crate identifiers reflowed `use {...}` lists
- noxis/examples/dbg.rs: allow unwrap_used/expect_used (scratch harness),
  add module doc

crates/noxis-classfile/tests/roundtrip.rs

@@ -6,6 +6,7 @@
 
 #![allow(clippy::expect_used, clippy::unwrap_used)]
 
+use noxis_classfile::{ClassFile, format};
 use ristretto_classfile::attributes::{
     Attribute as RtAttr, BootstrapMethod as RtBsm, ExceptionTableEntry as RtEntry,
     Instruction as Rt, LineNumber as RtLine, StackFrame as RtFrame,
@@ -14,7 +15,6 @@ use ristretto_classfile::{
     ClassAccessFlags, ClassFile as RtClass, ConstantPool, Field as RtField, FieldAccessFlags,
     FieldType, JAVA_21, Method as RtMethod, MethodAccessFlags, ReferenceKind,
 };
-use noxis_classfile::{ClassFile, format};
 
 /// Минимальный класс: версия, флаги, поле с `ConstantValue`, `SourceFile`.
 #[test]