Panic when enum variant with same name as another type

```cddl
hash = bytes .size (0..8)

non_overlap_basic_embed =  [
  ; @name identity
  tag: 0 //
  ; @name hash
  tag: 1, hash: bytes .size 32
]
```

This should be fine as it's prefixed as `NonOverlapBasicEmbed::Hash` but cddl-codegen panics during generation looking up `Hash` as an ident.